Marine fishkeeping, the complete beginners guide.

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Marine fishkeeping, the complete beginners guide.

Postby Bill19 » Fri May 08, 2009 7:37 pm

Something which has been a few years in the making :p I hope it is useful, and covers most bases. If you think anything is missing, mistyped, or wrong, don't hesitate to contact me :) Enjoy!

Marine fish keeping
The beginners guide

(Image credit-Race Fox)

Marine fish keeping
The beginners guide

Marine fish and coral with their vibrancy, interesting behaviour, and pure beauty are amazing things to have in your home. Firstly I would like to expel the myth that you should keep freshwater fish before keeping marine fish, yes they are a bit higher maintenance and more expensive, but it isn’t truly ‘hard’! The reason most people fail, or find it hard is that they treat it as a freshwater aquarium! Which is not the right way to go about it, they are so different you may as well forget almost everything you know about fresh water, any way...

Welcome to the salty side!

Is it right for me?
Marine fish keeping isn’t a doddle, and it certainly isn’t cheap, things can go right but then something can knock you right back. You have got to be dedicated, you have to be able to afford the necessary equipment (but you can get equipment bit by bit, or second hand) and most of all you have to care! Here are some factors to consider when choosing to go marine:
• There is quite a bit of equipment you have to use, can you afford the electricity bill, and initial out lay of cash?
• Most marine fish are wild, are you willing to keep wild fish?
• It is quite a lot of work, do you have the time?
• You will need to use RO water for a reef, making RO wastes a lot of water, and a large reef tank can use a lot of electricity, are you OK with making the environmental impact?
You ready?

The Equipment

The heart of any aquarium

The filter is the most important thing in your aquarium! No wonder there’s so many ways of doing it! Berlin, ecosystem, etc. I won’t be explaining all of these things just what make the basis of a good simple filtration system. All filter medium need flow through them for it to do any good! The tanks water needs to be circulated through the media at least 10 x the tanks total volume per hour (e.g. 100 litre tanks will need 1000lph pump). The filter media (apart from all of the live rock) can be put in an external canister filter, a sump, a trickle filter, or any other conventional filter.

“What’s a sump?” I here you ask, a sump is a tank underneath the display tank in the cabinet, it contains most of the filtration equipment and media. The sump has many chambers for the things to go in. The most common way of getting the water in to the sump is to have a weir or over flow (you can buy tanks with these already done, but you can do it yourself, but you need to read to about it and know what you are doing before going ahead), it is basically a hole in the bottom of the tank, but it is a behind a barrier, the height of the water level, so the water has to over flow over that barrier. Then it goes in to the sump, flows through the chambers and media, and the last chamber contains a return pump and it is took back up and back in to the aquarium. Sumps are fantastic as they give you lots of extra volume, and you can hide all the ugly equipment in there, out of site! But you don’t have to have one, but they are recommended!

Filtration is broken down in to three main types:
• Biological- This is probably the most important yet the most complicated scientifically of the types of filtration. Basically, fish waist, dying animals and plants, and rotting food, (decomposition of organic products) produce ammonia (NH3+), a very toxic compound which you need to be 0ppm at all times, special bacteria change this ammonia in to a less toxic nitrogen compound called nitrite (NO2-).
Nitrite should also always be 0ppm, it is not as lethal as ammonia, but still dangerous especially to invertebrates!
Nitrite is then broke down further by the good bacteria in an even less toxic compound called nitrate (NO3-). In a reef aquarium this needs to be as low as possible, preferably 10-20ppm or less. For a fish only aquarium 20-30ppm is a goal, but it’s OK for it to be a bit higher. But if it gets to 50 or above you need to be looking at your system and seeing where the problem is coming from, although the fish will be able to tolerate it, it’s still not the best for them, and a level of over 100 should definitely be avoided! High nitrate can also cause problem algae to flourish. Nitrate can be took up by algae, but nitrifying bacteria deep in live rock, will turn the nitrate in to nitrogen gas, which will go back in to the atmosphere, but not all the nitrate can be dealt with like this unfortunately!
Here’s a diagram from the internet which will help explain it:

For Biological filtration to happen, you have to have the bacteria, they need a substrate to live in/on . Bio balls and ceramic media can be used for this along with other commercial items, but they aren’t the best, what you should use and what all great marine systems are based on is, live rock. Live rock is not rock which can walk and talk, it is very porous rock which is from reefs (although some, now a days is ‘eco rock’ which is rock we made our selves, which is still teeming with life, so we aren’t relying of ‘wild’ reef live rock). Inside the live rocks thousands of holes live the bacteria, along with lots of micro fauna like copepods, crabs, shrimps, bristle worms etc. You need at least 1kg of live rock per 10 litres to sufficiently filter the aquarium for moderate stocking. Also you can get live sand where bacteria and micro fauna can also live, however there is little point in buying live sand, as it will be seeded buy the live rock. Live rock is also is used to decorate a tank so most of it is not kept in a filter. Live rock is better than any other biological filter media because only large lumps of live rock, which have area with no oxygen, can be home to the nitrifying bacteria which turn nitrates into nitrogen gas.

I also mentioned earlier that nitrate can be absorbed by plants and algae; this is where a refugium comes in. A refugium is a no fish zone, and it contains macro algae (caulerpa and cheato are the most common algae used, but cheato is the preferred algae), it can also contain, live rock, or a deep sand bed. Plants can sometimes be used such as sea grass (hard to get hold of) or even small mangrove trees! The refugium needs to be lit, a small compact light (such as an arc pod light or solaris light) are commonly used. Many people light refugiums 24/7, however this can lead to the plant being unhealthy, and any micro fauna living in it to die, it would be like us with the sun out all the time! I would recommend a lighting period for a refugium to be on the opposite cycle of the main tank, so when the main tank is lit, it is of, and vice versa. A refugium can be put in the sump, can be hung on the tank, or you can modify a standard filter to have one! All you need is light and the algae! But refugiums don’t just remove unwanted compounds such as nitrates and phosphates, the algae also provides a home and food for micro fauna such as copepods and other things which are a valuable natural food source for many fish.

• The next type of filtration is mechanical. This is an awful lot more simple! It is the removal of small and large particles. It is simply done by filter wool/floss or sponge. The filter wool/floss or sponge needs to be washed (under tap then rinsed in RO) or changed every week, the trapped debris will start to degrade and cause more ammonia to be put in to the system which will turn in to more nitrate! I prefer filter wool as it is cheap so can easily be changed weekly

• The last type is chemical; it is the absorption of molecular compounds in the water by a filter medium. The most common of these is the tiny bubbles of a protein skimmer. A protein skimmer is a cylinder contraption which can be hung on, or sat in the aquarium (depending on model), it releases tiny bubbles (either via a wood diffuser with an air pump or air injection), the protein skimmer is the best thing to do this, my motto is, if you can afford and fit one, get one! And also try and over skim, go for a skimmer which the manufacturer’s rate is suitable for a tank which is double your tank size. If you can’t fit or afford one, then don’t, chemical filtration can be done my other mediums, such as carbon, and seachems purigen, there are also many other products out there for you to find, but it all starts to get a little be too much like a science lesson!

Those are the three main bits of filtration, however there is one more compound which you need to keep to minimal levels, it is called phosphate (PO4), like nitrogen compounds it is from organic waste products. It needs to be kept as close to 0ppm as possible, as it will stress out and kill invertebrates. To keep phosphate down there is many phosphate removers on the market which remove it sufficiently, plants and algae also take in phosphate like they do nitrate, so a refugium can help too!

RO water
RO (reverse-osmosis) water will need to be used in modern day marine aquarium. This is basically water which has been put through a special filter to remove pretty much everything! You can either buy it from an LFS (local fish shop), or make your own! If you’re going to have a relatively large aquarium of say 200 litres you are probably better off with your own RO unit, but if your aquarium is a small nano, because of the small amount you will use, you just won’t make your money back on the unit, and would be better off buying your water from you local fish shop (LFS). However, LFS sometimes don’t change the filters as often as they should, so the RO water may not be optimum, and may already come with some nitrates, which it shouldn’t.

Light and heat

The next components are also very important, but relatively simple:
• Heat- Tropical marine fish and invertebrates need a constant temperature of 24-26c (75-79F). All you need to do this is a glass aquarium heater, put it horizontal at the bottom of a tank preferably in a high flow area (e.g. next to a filter intake, under a pump or power head). You can get different wattages for different size tanks, the manufacturers will state which size is right for what size tank.
• Lighting- The lighting you usually get with tanks now a days are T5 tubes, or compact (PL) bulbs. T5s is most commonly used, but T8 will suffice for a fish only aquarium, but I will come on to how much light in the coral chapter. A good colour light mixture is, half blue, half white, this is good for most corals and shows of the fish colours better, and it looks a lot more ocean like. The king of lighting is metal halides, these are very bright, and most large reefs use them, they come in wattages from 70w to 1000w! They also direct light in beams like the sun, so you get a ‘shimmer’ effect like you do in the ocean. The drawback of metal halides however, is that they are expensive to run, and they get very hot and can make the tank over heat! (I will address the problem next). There is another way to get the ‘shimmer’ effect, without the electricity bills and heat! LED’s. At the moment the only LED’s readily available are TMC aquarays and beams. You can light a tank solely with LED’s, or use them to supplement T5 bulbs, another advantage of LED’s are that you only have to change the units every ten years, whereas with fluorescents, you have to change the tubes twice a year!
• Cooling- yep, aquarium equipment gives of heat, especially lights such as metal halides! Most tanks in the UK fitted with fluorescent lighting don’t have a problem with overheating, however on a hot day, an aquarium can easily over heat, so you may need to cool your tank! The best way to cool a tank is a chiller, however these are expensive to run and buy, but well worth the money if you have serious heating problems. Most people how ever just use fans, to cool the metal halides, and to force evaporation to cool the tank down. It’s wise to keep a few RO ice cubes in the freezer in case of any overheating emergency.

As I said earlier a marine tanks volume needs to be circulated at least 10x an hour for it to be sufficiently biologically filtered. The filter pump will usually deliver this. However if you want to keep corals then you need it be circulated around 20x an hour or preferably more (depends on the coral species). This extra flow is provided by power heads, these are basically just pumps which are kept inside your aquarium! The best power heads are ones which have a wide `out flow’ point, so the flow isn’t one jet, and more of a flow. It is better to have more smaller power heads then large one, as this will make more natural flow patterns and will disturb more areas (to get rid of debris). Also on the market today there are wave makers, these are fantastic and really make natural flow! It rocks the water back and forth like waves do, and unlike power heads, you only need one or two!

The little things
Test kits, salt, nets, dosing bottles, fish food, spare media and equipment, etc. All these little things are very important. And neatly brings me on to...


Well obviously the water needs salt! A good brand of salt is essential, to buffer the water, and add minerals such as calcium and magnesium. Your salt levels are measured in salinity, it should be at about 35-37ppt at all times. A stable salinity is essential to a healthy reef aquarium. Salt levels can swing dramatically (especially in nano (120 litres and less) aquaria) if you have lots of evaporation often caused by hot weather or metal halides. So a top up system is a good way forward for tank owners with lots of evaporation, this is basically an external body of fresh RO water, which is dosed in to a tank by a dosing system, or this can be simply be done manually daily.
To measure salt you use a refractometer, or a hydrometer, refractometers how ever are much more reliable.

Testing... 1, 2, 3
You can test for a whole range of things, even weird things like boron! To test for these things (apart from temperature) you need test kits, which are usually liquid tests involving test tubes, or dip tests, the prior are more accurate, however the second is a good cheaper option, but not very accurate. Or you can get special electrical gadgets, but these are pretty expensive! As I mentioned earlier you will need to test for nitrate, nitrite, and ammonia. There are other things you must test for, temperature (via thermometer), salinity/specific gravity (salt levels, see above) and Ph. Ph is how acidic or alkaline something is, sea water is alkaline, and needs to be between 8-8.3. Decent salt (see above) will buffer your water usually.

There are loads of other gadgets out there for marine fish keeping and reefing, however the average beginner aquarium doesn’t need them. These are things like calcium reactors (used to put back in calcium which is removed by hard corals), phosphate reactors, nitrate filters, and UV sterilisers.

The Tank
Well you need something to put the equipment in... and the fish!

Size does matter

The bigger the better! Water is much more stable when in a larger quantity, so there for more easier to maintain. Generally 150-250 litre aquariums are a good size to start with, its big enough be stable, but small enough to not be too expensive. If you can fit a 200 litre aquarium, then don’t be scared to start with something smaller. I would recommend looking at fish in your aquatics and online, seeing which ones you really want to keep, then multiply that fish’s body length by 6 (a very rough guide to tank size needs), that is the minimum length of the aquarium this fish needs, multiply by 2, or preferably 3, for the minimum width needed. So a yellow tang (Zebrasoma flavescens) can get to 20cm so there for need a minimum of 120cmx 40cm tank, however 60cm width is much more recommended! However this doesn’t count for eels, since they are very long yet quite inactive, so don’t need a full 6 times swimming length, as they won’t use it like a surgeonfish would, and it doesn’t work for very small fish, and doesn’t mean you can keep a trimma goby(Trimma sp.) (grows to around 3cm long if that) in a 18cmx6cm tank!

Specifically reef tanks, general plug and plays, or a blank ‘canvas’?

(E.g. Orca nano, juwel lido, or clearseal?)
You have three main choices when picking a tank:
• Specifically reef plug and plays- these are tanks designed to be used for marines, usually they come equipped with the major equipment, however most people change the filter media for more suitable and better stuff, (such as remove bio balls and using live rock instead) and most people add a power head or two. On offer for you are the Red sea max, Orca nano, D-D nano cube, River-reef nano etc. The most popular is probably the orca, just shop around and see which is right for you. These are probably the best for beginners, as they are pretty equipped, and easy to get going.
• Plug and plays- These are tanks usually used for freshwater fish, however they can be converted. But you would have to change the lights, the filter media, and add power heads, protein skimmers etc. But sometimes it can be hard to add equipment due to hoods, so some plastic hacking is often involved. There are a lot of these aquarium ranges on offer for you, such as Aqua one, Juwel, and Rena. These are pretty good, but there are a few modifications you have to make to turn them in to a marine reef aquarium.
• Blank ‘canvas’- These tanks are just that, tanks, nothing else. These are usually preferred by reefers who want to make a tank for exactly they want! These are very good choice for more experienced aquarists, however as a beginner you aren’t used to all the equipment, and it would truly be jumping in to the deep end, and I would only recommend trying it if you have experienced fish keepers (on a forum or in real life) there to help you. There are a few places you can get these, such as and many other sites. You can get the tanks with backgrounds, or get them drilled with a weir (for a sump), with a hood and cabinet, depends what your after! And you can often get whatever size you want!
Last edited by Bill19 on Thu Apr 26, 2012 4:20 pm, edited 4 times in total.
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Postby Bill19 » Thu Aug 06, 2009 1:02 pm

Setting up

Now you have got the gear, you can get going!

First things first

So where do you start? Here’s a basic step by step run through.

1. Put the tank up; add the equipment in suitable places. Put the heater near to the bottom, horizontally, and ideally below a pump. Put the power heads on the side of the aquarium, one on either side if you have two.

2. Clean the inside of the tank and equipment to get rid of dust, and check for leaks
3. Fill the tank with RO water

4. Switch all the equipment on, and add the salt to the manufacturer’s advice.

5. Let the water warm up and all the salt to dissolve, and measure the salt levels, Ph, and temperature.

6. Once all those levels are perfect, and have been for a couple of days, you can add the CURED live rock! (non cured live rock doesn’t have life on it) (later I will talk about aqua-scaping, and rock safety) But make sure to remove some water before putting in the rock, or the tank will over flow!

7. Then you can pour in the sand! (coral sand or aragonite sand is good), and then top back up with the water you took out earlier.

8. Once you have added live rock and sand, before adding any living thing you MUST let the tank cycle! This links in with the biological filtration part. Basically once the cycle is complete, your tank will have lots of the good bacteria in it (remember them from the biological filtration section?). If you were to put a living thing in there straight away, it would release ammonia, but that ammonia would stay there! Most likely killing the inhabitant. So how do you cycle the aquarium? In a marine aquarium this is pretty simple, when you transport the live rock, some of the life will die, and this dieing matter will release ammonia in to the tank. There will be some bacteria in the live rock, already. So some of that will exchange it to nitrite, and then to nitrate, and more bacteria will grow, and grow. You will notice a peak in your ammonia readings, and then the ammonia will fall. Then you will notice a peak in your nitrite readings, and then they fall, and then the nitrates will build up and may fall a little, but usually not completely. It is important to keep the Ph, salt levels, and temperature stable, so to not kill the bacteria. You need to test very often during the cycle (every few days) as well to monitor nutrient levels. So when both ammonia and nitrite are 0, you should do a water change, as you may find your nitrates will be high. Then you can add your first critters! (more on live stock soon)


Before we get down to the arty stuff, you should try and follow a few guidelines to make sure you aquarium rock structure is safe:
• Place your rock on egg crate, so there are no pressure points on the glass.
• Make sure you put rock in before the sand!
• Stick the rock structure together with something (either something like miliput or on a pipe), so they don’t fall over, but the wobble method, is often used, if your rock structure cannot be wobbled, a fish isn’t going to be able to easily move it, so is pretty safe.

So now to the more arty stuff. There are two main ways to go about scaping, ones way is planning what it will look like, and the other is getting your rock and then just put it together on the spot. Different things work for different people, but if you really want a good scape, you may need to plan just a little!
Unlike in some planted tanks marine aquarium scaping is really about replicating a natural reef, and in my opinion a slope from one side of the tank to the other or a hill in the middle really isn’t that natural and just looks pretty boring. Two hills looks better but still isn’t that impressive. But one of the best ways to make a tank look natural is to not have rock touching the back or side of the tank, so that the scape is say in the middle (or towards the back a little more) of the tank, but not against the wall. This means that fish can swim all the way around the rock, and corals can disappear behind the rock, this makes us think there is something behind and beyond it, therefore doing its job as replicating a real reef! To help you recreate these hills, you can make egg crate shelves, or base rock, so that it bulks it up some more, the best base rock is almost live rock, but it is not as porous, so doesn’t carry as much life and doesn’t have such a big price! Also dead live rock can be great, as it will eventually turn in to ordinary live rock!

Some of the best scapes I have seen are based not on large hills and mounts, but on pipes! These scapes are basically rock which is attached to pipes, so you can make towers, bridges and a whole intricate scape! So how do you do it? I don’t know either so I contacted east916 (a.k.a Anthony) , who has a brilliant aquascape based on this technique, and asked him how:

What sort of rod or pipe can you use?

“I used domestic overflow pipe, the same pipe that was used for the sump return pump pipe & spraybar. As you know I also drilled this pipe (*with numerous holes) and connected a pump (in my case an external filter) to it to give flow directly onto the rock (*to aid biological filtration). This also helped with keeping the frame in position, as otherwise a sealed plastic framework would be very buoyant until the rock was attached. You could use any plastic piping for this as long as you take into account:
A. the weight of the rock, so make sure it's strong enough.
B. the fact that you want to hide the pipe, so nothing to big.
C. whatever material you use is fish-safe..”

How do you attach the rock to the pipe?

“I used plastic cable ties to attach the rock to the pipe. This was done by drilling a small hole through protruding sections on the back of the rock. Position the rock first, put your finger where the tie needs to go, and drill it.”

Is there anything special required to drill live rock?

“I used a 7mm standard masonry drill bit. I drilled the rock under water with a long bit so as not to affect the 'living' element, but a few seconds out of water probably wouldn't harm it too much.”

Anything else we should know, in general?

“Just make sure the whole thing is stable, as it will have a lot of weight on it. You will need some sort of 'foot'. I built a square section of pipe at the base of each end for this.”

Any tips?

“Don't glue anything until your absolutely sure your happy with your design and the whole thing is fully built. You'll be amazed how much tinkering can be involved”
*authors notes

Here is some pictures of his aquascape before rock and after


You don’t have to construct whole scapes using this technique, just making pillars, arches and other interesting things will add extra interest to a plain old hill.
Try to add arches, bridges, and lots of caves to you aquascape, this will not only make the tank look more interesting, but it will enrich the fish’s live by having things to hide in, sleep in, and swim through!
Last edited by Bill19 on Sun Apr 22, 2012 5:07 pm, edited 3 times in total.
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Postby Bill19 » Sat Aug 15, 2009 9:07 pm


Before we get on to the good stuff (stocking!) you have to know how to maintain the tank first! Here is a list of the general maintenance which you need to do, excluding feeding the fish:

• Water changes, 10% every two weeks is sufficient for a tank with a good protein skimmer, and even monthly water changes would be ok in a low stocked tank with lots of filtration! However to maintain optimum water chemistry a 10% or so water change ever 2 weeks is good (in the average beginners set up with a skimmer) (if no skimmer then really a weekly change is needed when keeping less hardy invertabrates). We water change not only to reduce nitrogen compound levels, but also to replenish trace levels, such as calcium, iodine and magnesium. Don’t forget the water you add must match up to the current tank water (in temperature, salt levels, and Ph)!
• Topping up, I touched on this earlier; water inevitably evaporates, so to keep the salt levels constant, you must top up, with unsalted RO water! Basically mark on the tank somehow, how full the tank is at optimum salt levels, then ias you notice the water go below this line, top up with RO until it is at the line again, this may have to be done daily. If you can’t be bothered to do this your self then you can invest in a auto top up system, which does the work for you!
• Replacing light bulbs, fluorescent tubes need to be replaced every 6 to 8 months to make sure you have the optimum light spectrum, if you do not do this you may find your corals start to not do as well, but unwanted algae does very well! The change in spectrum may not be visible to our eyes, but it does change! You also need to change metal halide bulbs, you need to change these every 8 to 12 months.
• Dosing- some corals have calcium based hard skeletons, and they require lots of calcium and magnesium to build these, so these can deplete in an aquarium with lots of hard corals quite quickly, which can cause other problems such as with Ph, you can dose manually form bottles, or buy special reactors.
• Testing and checking, you "should" test for all of your parameters at least once a week (but in a mature system with routine maintenance, you can test less), and temperature daily. Every day you must almost check that all the equipment is working properly, and that all of your stock is present, eating and healthy!
• Algae cleaning, you may not have to do much if your set up isn’t over stock, isn’t over fed, and have enough filtration, you shouldn’t get that much algae. The stuff which you do get is most likely going to be on the glass, and to clean this of it is very easy, simply buy a algae magnet, one side of the magnet sits on the inside of the aquarium, the other on the outside, so you can rub of the algae, with no wet hands!
Last edited by Bill19 on Thu Apr 26, 2012 4:13 pm, edited 4 times in total.
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Postby Bill19 » Thu Apr 26, 2012 4:17 pm


Now you have your tank, its set up, cycled, and ready, now you can have some fun! There are 100’s of species of fish, invertabrates, corals and even some plants out there to choose from to put in your tank, but these numbers are limited by your set up. This section is really quite a brief over view on stocking your aquarium, and will hopefully just be a starting point for your research.


What fish can I have?
This is a very common question, once you really start to look past the usual clownfish and tangs, there is a whole labyrinth of fish out there to choose from, but what should you consider when choosing fish?
• Size- the biggest limiting factor to what fish you can have is the size of your tank, and how much room that fish needs. A basic rule of thumb, is that the maximum size of fish you can have is your tank length divided by 6. So the maximum length of fish suitable for a 60cm tank would be a 10 cm fish, and the maximum in a 180cm tank would be a 30 cm fish. But this has to be a bit of a judgment call on your behalf, and active fish need more room than docile fish. Some fish such as tangs are extremely active, and a large stocky 30cm long regal tang, which is a very active swimmer, could be considered too large even for a 6 foot tank, and an active 10cm dwarf angelfish definitly seems a bit squashed in a 60cm tank! But a metre long moray eel certainly doesn’t need a 6 metre long aquarium, and you can’t keep a 3cm long trimma goby in a 12cm tank!
• Ease of care- when starting out, it’s better to begin with hardy fish, which could survive any accidents and mistakes you make, and will allow you to settle in to the hobby. At first try and avoid fish which are fussy feeders (e.g. mandarinfish), prone to disease (powder blue tangs), and fish which need specialist care (e.g. seahorses).
• Compatibility- can the species you want get along together in a confined space? You can’t keep aggressive boisterous fish with placid shy fish, and it is obviously not wise to house large predatory fish with small fish! Also you need to check how compatible your fish are with invertebrates and coral. Here’s a really great tool to see what fish are compatible with each other:
• Numbers- another thing to consider is if a fish is social or not. Shoaling fish such as anthias and some cardinal fish really need to be kept in shoals (as a quick tip, when purchasing a shoal of fish, buy in odd numbers- for some reason, they get on better together), but some fish shouldn’t be kept in groups (such as firefish, if you buy a shoal, 2 fish will pair up and kill the others), and some fish prefer to be in pairs (such as clownfish). But some fish shouldn’t be attempted to be kept in groups or pairs at all and should be kept on their own.
• Specific needs- before buying a fish you should investigate any special needs that fish has, for example is the fish a herbivore and needs to be fad accordingly, or does the fish like to make a burrow and needs a deep sand bed?

How many can I have?
The next question people will ask is how many fish can they have? This unfortunately can’t be answered easily, and is specific to each set up. A very basic rule is that you can have 1 cm of fish for every 3 litres of water- so for examples if you had a 60 litre tank, you could apparently have around 20cm of fish, which would mean you could have say 2 percula clownfish (8cm each) and a clown goby (4cm). But obviously this does not always work and the amount of fish you can have all depends on these things:
• Water quality- the more fish you have, the more waste is created and the worse your water quality will be, if you over stock, your nutrient (nitrate etc) levels could get too high and be detrimental to your tank. How good your filtration is and how many water changes you do could mean you could keep more or less fish.
• Territory- usually the water quality problem comes first, but if you had masses of filtration and a relatively small tank, eventually, you will get to the point where the fish will simply not have enough space!
So really the best way to go about stocking numbers is, make an estimation using the 1cm for 3 litres of water rule, and stock your tank slowly, keeping an eye on the nitrates on your tank, and quite simply stop stocking when you feel nitrates start to get higher than you would like, or the fish start to look a bit cramped!

What order do I introduce fish in?
Another common question, and a pretty simple answer, try and introduce shyer smaller fish first, and leave larger more territorial fish till last!

Feeding fish
Fish need a varied diet, and there are lots of options out there:
• Flake food and pellets are the commonest foods used, especially the former, and a decent make of marine flake food provides fish with a whole mix of nutrients and foods. Most easier to keep fish will eat flake food, but some more difficult fish won’t touch it, or at least need weaning onto it.
• Frozen food- probably the best food to give your fish, it is eaten readily by most aquarium fish and provides fish with lots of nutrients.
• Live foods- live shrimps and such are often needed to feed very picky eaters, but usually aren’t necessary.
When feeding your fish you need to consider their natural diet (herbivore or carnivore?) and how big their mouths are (it sounds obvious, but don’t go feeding a little goby a whopping pellet)!
Most people tend to feed their fish a variety of different frozen foods, as well as supplementing it with flake foods.
Rules on feeding:
• A general rule is to feed fish twice a day, but some fish like to be fed little and often, such as anthias
• Don’t over feed! This is quite an important one, and it is often claimed in the fishkeeping world more fish are killed by over feeding than under feeding! Feed fish slowly and a bit at a time, and don’t feed more than they can eat in 3 or so minutes, the last thing you need is a load of fish food on the bottom of the tank rotting away!
• When feeding frozen food, always fully thaw it first, and then drain off the water down the sink, just leaving the food.

You need to observe your fish, and notice any changes in behaviour, markings, or feeding, as all could be symptoms that your fish are ill. Illness in fish can be caused by bacteria and viruses, stress, and is often linked to high nitrate or ammonia levels. Good maintenance and stocking and care can usually prevent bad water quality and stress, but stopping the spread of parasites and bacteria/viruses from your aquatics to your own tank can be trickier. The only way to truly combat the issue of accidently introducing a fish into your aquarium which is carrying something is to quarantine your fish. This involves keeping a fish in a temporary separate aquarium for a period of time to make sure the fish is safe to put in. Not everyone bothers to quarantine, but it’s often heavily advised when keeping fish which are sensitive to illnesses.

Reef critters and corals
The main two types of marine aquarium are fish only (or a FOWLR- fish only with live rock), and a reef tank. A fish only tank, is quite literally a tank with just fish in it, but a reef aquarium also has invertebrates such as shrimps and crabs, as well as corals. You must bear in mind though, that invertebrates are harder to keep than just fish on their own, they require better water quality and are more effected by swings in salinity and other parameters, but if you have followed this guide so far, you should have no problem!

Non-sessile invertebrates
Sessile means not moving, and so non-sessile invertabrates includes things like crabs, snails and shrimps, which quite obviously, move! Invertebrates often just feed on the same food you feed your fish, and are pretty low maintenance and look after themselves (in most cases, some invertabrates do have specialist needs), and they have very little effect on the bioload of the tank, so you can stock quite a few of them as long as they have enough space. The great thing about these types of critters is they actually can work for us!

The clean-up crew
CUC/clean-up crew is a phrase commonly thrown around the reefkeeping world, and is attributed to a team of invertebrates which live on your mini reef and help to keep it clean! A clean-up crew is an important part of the reef ecosystem, they eat uneaten fish food, detritus, help to stir the sandbed, and munch on algae. A clean-up crew usually consists of snails, some species of which clean algae of the glass, some move under the sand and stir the sandbed, and crabs or shrimps which eat scraps and algae.

Corals are what really turn a fish tank into a reef, but they do have some special requirements:
• Lighting- corals need light just like plants do, to photosynthesise, and different corals need different amounts of light, so do you research!
• Flow- corals also need water movement, but once again different corals need different amounts of flow!
• Trace elements- trace elements are things like minerals and metals, such as calcium and magnesium, both of which are needed by corals which grow a calcium based skeleton, known as hard corals, but soft corals need such trace elements as well, but soft corals don’t use enough of these trace elements to need to monitor their levels or dose them. (water changes help to replenish these elements and minerals)
• Feeding- most corals will be benefited from the odd feeding, and some corals will happily eat fish food which happens to land on them, but some corals need feeding to survive because they don’t contain the algae which are used by other corals to photosynthesise and provide them with nutrients. Some corals such as gorgonians need to be fed plankton and can be difficult to cater for, some need to be directly fed daily with small frozen foods. Al these corals are high maintenance and perhaps best avoided at first.
Just like planting plants in your garden, you need to put corals in suitable places in your tank, for example of a coral needs lots of light and high flow, make sure it goes high up in the tank and in a high flow area close to your power heads. You also need to think about how aggressive corals are, which at first may sound a ridiculous concept, but corals have to fight (sometimes quite literally) to get their place on the reef and it will happen in your tank as well. Some corals simply grow quickly and shade out other corals, some sting each other to fend off and kill neighbouring corals, and some even release chemicals into the water to stop neighbouring corals getting too close. So place corals a suitable distance from each other, and don’t go putting a defenceless coral next to an aggressive stinging one.

Buying and introducing your stock
Before buying a fish, invertebrates or coral you must research it, and asking the aquatics shop doesn’t qualify, many aquatic shops out there don’t give out great advice, and often will just try and sneak a sale out of a inexperienced costumer. Get to know your aquatics to see if they are trust worthy, and any good aquatics will let you reserve a fish while you do a bit of research on it. When choosing stock for your tank, be picky, only go for fish you really want to keep, and here are some things to look out for:
• Health and behaviour- obviously you don’t want to buy a sick fish, so look if it is acting normally, is it swimming around confidently? Look for any signs of illness such as spots and parasites, and don’t buy a fish which seems stressed. Something else to bare in mind is how long the fish has been at the shop for, if its new there, it may not have had time to show any sign of illness, or could still be very stressed.
• Feeding- make sure the fish doesn’t look skinny, and looks rounded and full. Ask someone to feed the fish with some frozen food to see if the fish will eat it (make sure you actually see the fish eat the food, don’t be fooled by a fish which takes some in its mouth just to spit it out again).
• Make sure you only buy corals which are opened up and look healthy, check and see if you can see any signs of parasites
After buying your fish, get it home as quickly as possible; don’t go for a super market shop on the way home! One of the best ways to transport stock is to put them in empty a freezer bag, as this will help insulate the heat.

All living things can’t just be chucked into your tank straight from the bag, you must first acclimatise them to the tank, as always, nothing good happens quickly in fishkeeping. Acclimatising allows the fish or invertebrate to adjust to your aquarium water, which could be a bit different to the water at your local fish shop. Acclimatising basically involves you gradually making the temperature, pH, and salinity of the water in the bag match that of your aquarium water, this is done by gradually adding water from your tank into the bag.
Most people float the fish bag in the aquarium to help it get up to temperature, and for fish, gradually by hand add in water from the aquarium a small bit at a time (about half a cup every 5 minutes or so) until the bag water matches the aquarium water, then you can net the fish and let it go into the aquarium. If the fish starts to show major signs of stress (i.e unnatural behaviour- such as sitting still and gasping rapidly), then stop adding in water and let the fish pick up again. You should not put water from this bag into the aquarium, as it could be soiled, and the fish shop could have used copper treatments in the water which could kill invertebrates.
Acclimatising invertebrates such as shrimps, crabs and snails, is a much slower affair. It can be done in the same way I described for fish, but you must add less water at a time, and at more distanced intervals, because they are more sensitive to change in water pH and salinity. The drip method is a better way of insuring a slow acclimatisation of invertebrates, and some people acclimatise fish this way just to be doubly sure they are doing it slow enough, and it’s easier! The drip method starts of like the above method, start by floating the bag in your aquarium for it to get up to temperature. Next put your bag below the aquarium surface level, this could mean putting the bag in a jug or bucket, and open it up. Now what you need is some airline tubing and a control valve. Create a syphon with this tubing by submerging the pipe in the water, letting it fill with water, and then covering one end with your finger, leaving the other end in the tank, move this sealed end over the bucket and let go. Use the drip valve (or potentially by tying a knot in the pipe and tightening or loosening it) to limit the flow of water to just 2-4 drips per second. After the water volume has doubles, discard half the water and continue the dripping. Once the water in the bucket matches that of the tank, you can carefully add your invertebrate to the aquarium. You can add some of this water back into the tank if you like.
Acclimatising corals has often been done in the same way as the higher invertebrates (crabs, shrimps etc, by the drip method), however due to their completely different anatomy, they are nowhere near as sensitive to changes as shrimps, crabs and snails are. Some people just let their corals adjust to temperature by floating them and then adding them straight to the tank, but perhaps for some peace of mind many introduce them in the same way to fish or at least in a quicker manner.

Fish, corals, and invertebrates for beginners
Here are just a few examples of easy to keep inhabitants for your aquarium, and a little bit of information about hem for you to go on and research further.
• Common clownfish- one of the most well-known marine fishes thanks to the infamous Disney classic, Finding Nemo, and for their symbiotic relationship with sea anemones! Common clownfish grow to around 7cm long, so can be kept in smaller aquaria of around 80 litres in size. The great thing about clownfish is they are readily available as tank bred specimens, and these fish are very hardy and better feeders than wild fish, so always buy captive bred stock. Clownfish are best kept in pairs (buy any two small clownfish, and your guaranteed a male female pair, because all clownfish are born male and one will change into a female!), and show some great behaviour, from hosting corals in your aquarium, to the funny little vibration dances the male does for the female which is thought to show his submissiveness.
• Midas blenny- a fish belonging to a family characterised by what I think is a goofy and gormless face, and to match this they show lots of great character and activity. They can grow up to 10 cm, and need a tank of around 150 litres. They are hardy fish which readily adapt to frozen and flake food.
• Yellow tang- these large, very brightly coloured and active fish need a tank size with a minimum length of 4 ft long for them to stretch their fins! They are one of the easier tangs to keep, but still can be sensitive to the disease white spot like all tangs. They are primarily vegetarians so need to be fed accordingly (vegetarian flakes, nori, and real sea weed), and will pick at your rocks, but will also relish the usual flakes and frozen foods.

• Scarlet hermit crabs- these little crabs are readily used in clean-up crews and feed themselves by picking at algae and left over fish food. They pretty much look after themselves, and can be very entertaining to watch, in my eyes, no reef is complete without a hermit crab! These crabs need to be provided with empty snail shells of various sizes so when they grow out of their current home, they can find a new one without having to kill a snail just to steal its home!
• Turbo snails- these snails are also very valuable cleanup crew, they eat algae of the glass and rocks. But don’t over stock your tank with snails, they can easily eat themselves out of food and will starve
• Skunk cleaner shrimp- no tank is complete without a shrimp scampering about stealing fish food virtually from your fingers! They add an extra bit of movement and colour to your tank, and also provide you with another member of the clean up crew, and some great behaviour to watch! Cleaner shrimp are called so because on the wild reefs they set up cleaning stations and clean parasites and particles off of fish, and the same can happen in your aquarium!

• Mushroom corals- the hardiest coral around, mushroom corals are also prolific breeders and inject good coverings of colour into your tank, and come in many colours and patterns. They don’t need much light, and prefer low flow, so great for low sheltered parts of your reef,
• Zoanthids- zoanthids are colourful little polyps, and like to have moderate lighting and flow, they come in a virtually endless array of colours, and a mass of zoanthids is a sight to behold!
• Leather corals- leather corals are all large hardy corals, there are numerous types from large toadstool corals to finger corals. Toadstool corals often become surrogate anemones for clownfish, and large finger corals can inject some height and movement into your tank. Leather corals need medium light and flow
• Pulsing xenia- named because the polyps open and close quickly as they move around in the aquariums flow, they are hardy corals which spread very quickly. They like to have moderate lighting and moderate to high amounts of flow.

Time to get buying!
So that should hopefully give you enough knowledge to get you going with your marine project, but the time for research is never over, the more you read, ask, and listen, the more prepared you will be. Owning your own little ecosystem, which is what a reef tank is, is very rewarding, and addictive! Soon you will want another tank, this time 5 times as big, with more fish, and harder to keep corals! But until then, I hope this guide has been useful, and if you have any questions, don’t hesitate to ask anything, no matter how stupid you may think it sounds, on the marine section of this forum!

Happy reefing!
Will always be a PFK teen ;)

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