Bronze Corydoras fry

For advice on breeding your fish or information on other members fish breeding successes look here.
Colsel
Posts: 36
Joined: Fri Dec 09, 2016 7:08 pm

Bronze Corydoras fry

Postby Colsel » Thu Apr 20, 2017 9:50 pm

I took some of my bronze corydoras eggs out of their Rio 125 and put them in a little tank. I now have about 10 little bronze corydoras fry that went from eggs to swimming fry a couple of hours ago. I have ordered some decapsulated brine shrimp eggs that should arrive by Saturday.

How long should I wait before feeding them the decapsulated brine shrimp? They eat their egg sack first?

Should I add a thin layer of sand to the bottom of their little tank?

Should I add an airstone or just change the water every day?

The tank is too small for a heater. Maybe I could float the tank in my Rio 125 or Rio 180? Why is the best temperature for the fry?

How long should I wait before putting them in the Rio 125? Thanks.

User avatar
Sjaak
Posts: 606
Joined: Mon Apr 04, 2016 4:14 pm
Location: East Lancashire

Re: Bronze Corydoras fry

Postby Sjaak » Sat Apr 22, 2017 6:07 pm

Hi Cosel.
When breeding Corys I add one or two drops of Liquifry to the tank twice a day, this is to feed the "Infusoria". The best place to find Infusoria is in the plant bases where there looks to be some "crud" or fuzzy gray/brown clumps. Collect it with a pipette.
The fry will also eat the Liquifry. You need to add the Infusoria and Liquifry NOW to get a culture going.
Decapsulated brine shrimp is a bit big for very young fry, I never use it as I have my own Microworm cultures and I have found the Cory prefer it.

Never use sand with freshly hatched fry or eggs as Cory can get bacterial infections in their bellys, after 8 weeks the baby fish will be ok on very fine sand.

Air Stones are usually essential with eggs and help to keep the water moving and oxygenated for the fry.

Big water changes are essential, and I mean big. As there is no filtration the nitrites will start to spike very rapidly. Ammonia should not be a problem if your water is below pH7.
Buy a good quality Nitrite test kit, JBL if you can get one and keep an eye on those Nitrites.

Wilkos do a 10l plastic tank for about £8 (I use them for my fry) and a 25W heater can be fitted horizontally .

Keep the water depth less than 5-6 inches as Cory fry sometimes need to break surface to gulp some air. If the water is deeper than 6" very small fry can't make it to the top.

Water Temp 23-24C works best for my fry.

I find it best to keep them in a growing on tank until they are two and a half moths old.

I hope I covered everything.

Good luck

Colsel
Posts: 36
Joined: Fri Dec 09, 2016 7:08 pm

Re: Bronze Corydoras fry

Postby Colsel » Sat Apr 29, 2017 9:36 pm

Thanks for the reply Sjaak.

I have 22 little Cory fry at the moment in a little tank that I float inside my Rio 180. I was doing a water change for my other aquarium, my Rio 125, and I found a cory fry. So I took him/her out and I put him/her in with the 22 so I now have 23. The fry that I found today must have been in there a while because he/she is twice as big as the other fry that I have.

I don't want any more eggs but my adult bronze corydoras keep leaving lots of eggs on the glass and I don't want to end up with too many bronze corydoras. Any advice?

I have a 3D background and although it has netting down the side I worry that tiny fry could somehow squeeze behind it.

User avatar
Sjaak
Posts: 606
Joined: Mon Apr 04, 2016 4:14 pm
Location: East Lancashire

Re: Bronze Corydoras fry

Postby Sjaak » Sat Apr 29, 2017 11:26 pm

Bad/good news, unfortunately you have created the perfect environment for your Corys, and they will just continue to breed. The only way to stop the breeding is to keep the water at a constant 24C with change water 30l at 26C and stop any live/frozen live food.
Get things right and fish breed, you got it right, nice one!

The fry/egg tank in a stocked tank is the best way to raise any fry as long as there is room in the main tank to do it, stand alone egg/fry tanks do not produce enough waste for filter bacteria to maintain the water quallity and this means that massive water changes are needed every day, so nice one again on the tank in tank method!

Bronze Cory are a bit "Ten a penny" to sell for cash, selling/trading any fish is dependant on having a good relationship with the owner. I would suggest that you go to a LFS, ask advice on rearing your fry (and ignore it), buy some Liquifry no1 and the smallest pot of TetraMin flake stocked. Fry will eat the Liquifry and any infusoria feeding on it, they will also eat tiny flakes off the bottom. I have found that Microworm is the best food for keeping Cory fry alive. Micro worm live in a puddle of soggy oats and smell like vinegar. Have a look on youtube for how to keep them. I bought my culture of Microworm from Tartan Tropicals nearly a year ago and have created a series of replacement cultures from it.
Back to the LFS, while you are there ask if they will give you store credit for your young Bronze Corys. 22 is a decent number to swap.
Young Bronze Corys look great, and any LFS owner that knows what he is doing will stick a note on the tank saying "Local tank bred" and they will fly out of the shop.

Now here is the bad news. You will need a growing out tank for the fry/young fish. As the fry/ young fish get bigger they release more CO2/carbonic acid, this will lower the pH of the main tank, it will probably/definately not overload a Juwel filter though. A good quality second hand tank with some filter media added from your Juwel tanks added at the same time as the young fish should keep the tank cycling, but you will have to keep testing the nitrites to make sure that it is biologically filtering the set up.

Don't worry about any fry being behind the background, if there are any there, they will feel safe and come out at night to feed when they are hungry.

I am chuffed to bits for you! Over the years, so many so called "fish keepers" have tried to breed fish and failed miserably, you got it right!
Welcome to the world of actually being a Fish Keeper!
If I have missed something you asked, please let me know.
Good luck
Sjaak

Colsel
Posts: 36
Joined: Fri Dec 09, 2016 7:08 pm

Re: Bronze Corydoras fry

Postby Colsel » Sat May 06, 2017 12:22 pm

Thanks for the reply Sjaak.

I have 27 fry now because I have found some in the Rio 125. I am still not sure as to when I should add a thin layer of sand? I know you said after 8 weeks and that sand can cause bacterial infection for fry but is the reason to not have sand to do with water quality?

I have read online where some people have said that they have higher survival rates when they add a thin layer of sand. I have 27 fry the now but 4 have died over the past two weeks.

I wish it was a clear or definite yes/no as to whether to have sand and at what stage to add it but there is conflicting opinions on it.

User avatar
Sjaak
Posts: 606
Joined: Mon Apr 04, 2016 4:14 pm
Location: East Lancashire

Re: Bronze Corydoras fry

Postby Sjaak » Sat May 06, 2017 2:51 pm

Hi again Colsel.
With a bare glass/plastic bottom it's much easier to see any debris/dead microworm in the tank (can be removed with a pipette).
I also find it easier to see how much food is on the bottom.
I used a sand substrate originally and the losses are much higher than on a bare bottom.
Good luck

Colsel
Posts: 36
Joined: Fri Dec 09, 2016 7:08 pm

Re: Bronze Corydoras fry

Postby Colsel » Sat May 06, 2017 3:16 pm

Thanks for the reply. I'll keep it without sand then until 8 weeks. I'll mark the date on my calendar. Thanks.

Colsel
Posts: 36
Joined: Fri Dec 09, 2016 7:08 pm

Re: Bronze Corydoras fry

Postby Colsel » Mon May 08, 2017 8:56 pm

When they're all fully grown, and I have 32 adult bronze corydoras, how many tetra tabimin tablets should I be giving them?

User avatar
Sjaak
Posts: 606
Joined: Mon Apr 04, 2016 4:14 pm
Location: East Lancashire

Re: Bronze Corydoras fry

Postby Sjaak » Mon May 08, 2017 10:45 pm

Hi Again Colsel.
I am not an expert on Bronze Corys. I can't keep them as my water is way too soft pH5.65 or lower if I choose, so basically if I kept them they would become stressed, develop Ich and die!
They grow up to 70mm, so working it out in my overworked brain; 32 adult fish would require a 240l tank ish ( it could be 180l, but I think nearer to 240l).
You could move them into something like a second hand Juwel Rio 125 and trade them when they get to about 3cm. 32 bottom dwelling fish is a lot even for a Rio 125 though. I know you did not ask about this, sorry if you had already worked it out.

One thing I am very sure of is that all Corys do best on a mixed diet; Flake that finds the substrate, Hikari Sinking Wafers (slightly crushed), the occasional skinned tinned pea and most important live food! I keep a few Grindal Worm colonies to feed all my fish fresh live food.
Avoid Daphnia live or frozen as if you get a "bad" batch it will kill Corys first. Don't feed brine shrimp as Corys and salt do not mix.
The amount of food is quite hard to judge with Corys. The bold species will be out and about feeding as soon as they detect food, the more timid species will wait till they feel safe and then feed. I feed mine twice a day and usually everything that hits the bottom is gone in up to an hour. If everything you feed them is gone in minutes just slightly increas the amount of food added. I what you have fed them is still there an hour and a half later then reduce the amount. It works for me. Yours are growing fish and will need more fish for their size than adult fish. You will soon work it out though.

Most important; Keep an eye on the nitrites at all times, go over 0.25ppm nitrites for too long and all the Corys will start to die a week or so later.

That's my brain emptied of all things Cory breeding related, probably.

As I said before, I am well chuffed for you. There are not many people on this or any other forum that have ever bred 32 of anything (other than live bearers or Cichlids).

NICE ONE!
Sjaak

Colsel
Posts: 36
Joined: Fri Dec 09, 2016 7:08 pm

Re: Bronze Corydoras fry

Postby Colsel » Tue May 09, 2017 6:14 pm

Thanks for the reply Sjaak.

At the moment all I have in my Rio 125 are the 5 adult bronze corydoras. In my Rio 180 I have a bristlenose plec and 12 black widow tetras. So I will eventually put 16 bronze corydoras in the Rio 125 and 16 bronze corydoras in the Rio 180. There should be enough filtration and its not overstocked according to an aquarium stocking calculator I used.

For filtration is it worthwhile to add an extra filter eg a fluval 2 plus internal etc? I already have an air pump for extra water movement.

At the moment I give the 5 adult bronze corydoras two tetra tabimin tablets and a little flake everyday and they always eat it all very quickly. I don't want to overfeed though so I'll need to think about how many tablets for 16 in each aquarium. I put vegetables in for the bristlenose plec like cucumber and potato so maybe the corydoras will try that? I also put in some tetra wafer mix tablets.

The only live food I've tried is bloodworm. Grindal Worm sounds interesting. I'll give it a try.

At the moment the fry are doing well and they will be 3 weeks old on Thursday. They look happy in their little tank that has about 5 inches of water. At what age should they move to their grow out tank how deep should the water be? 8 inches? 10 inches? At what age will they be big enough to go in the Rio 125/180 which is about 20 inches deep?

Thanks for your help.


Return to “Fish breeding”

Who is online

Users browsing this forum: No registered users and 2 guests