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Hello! In researching how to care for Cory eggs and fry I found this website, which means I'm new here!

I came home one day to find that my Corydoras Aeneus had laid 300+ eggs in my heavily planted 10 gallon aquarium. I have never kept eggs/fry before, and I would like to give it a shot. I have read the breeding guide in this forum and I am trying to follow it the best I can, I would just like to confirm that I am doing things right.

Upon seeing the eggs I guessed that they had only been there for about 4 hours, so I waited several hours before attempting to move them so my Dwarf Gourami does not eat them. I went out and got another 10 gallon aquarium, a heater, and a sponge filter. I rinsed my seasoned HOB filter media (2 bags) and sponge in a bucket with some dechlorinated water and began to violently squeeze and swish my box sponge filter around in it (I took 5 of the ceramic beads from the filter and placed them in the box as well). The box sponge filter is now running in my main tank in hopes that I speed up the seeding process before the eggs hatch.

Anyway, I set up my new bare-bottom tank, primed the water, and began surgically removing the eggs. I took a clean razor blade and scrapped all 300+ eggs into a small cup that I kept submerged in tank at all times so the eggs fell into the cup, and were not exposed to the air. I then went over to my new tank and placed them all on the wall after making sure the water temps were the same. I then took an airstone and placed the airstone in a way in which it provides some flow but doesn't knock them off - I can see the eggs swaying. I plan to only replace 10% of the water each day until the eggs hatch (apparently they're fertile, if you follow the breeding guide, they're a tan color). When they hatch (which I hope they do, I love Corys!) I plan to place the sponge filter in it and take the airstone out - the box sponge filter provides enough aeration I assume.

Am I doing everything okay so far? Will the eggs hatch okay in such a large volume of water (comparatively)? I tried to act as quickly as possible. I can't find methylene blue anywhere - the chem labs are closed for the holidays, too. Is there an alternative such as bettafix or some other form of antifungal? It has now been ~24 hours since they were deposited (I'm a neuroscientist, sorry if I am butchering the proper birth-nomenclature). Any help is appreciated! The eggs, I can see, are beginning to develop just a slight amount of fungus that I noticed only a few minutes ago. Thank you so much!

I'm in a similar situation as you. A couple of days ago a nice weather front came through my area and I found 300+ albino C. aeneus eggs. I'm using Primed tap water as well and running a sponge filter in a 2.5 gallon tank. I found an old bottle of Methelene Blue, but my eggs are still fungusing. I've heard of people using H2O2 as an antifungal treatment. Try doing a search on that method. I'm going to try it next time they spawn for me. Best of luck!

RobBob wrote:I'm in a similar situation as you. A couple of days ago a nice weather front came through my area and I found 300+ albino C. aeneus eggs. I'm using Primed tap water as well and running a sponge filter in a 2.5 gallon tank. I found an old bottle of Methelene Blue, but my eggs are still fungusing. I've heard of people using H2O2 as an antifungal treatment. Try doing a search on that method. I'm going to try it next time they spawn for me. Best of luck!

Thanks for the reply! I'm not sure if I want to go the peroxide route, but I will read up on it. I guess it can't be all that harmful if I'm diluting it in 10 gallons of water (plus the pre-dilution in the bottle). Do you know whether or not my set up will be capable of hatching these eggs? It looks a little weird having 300 eggs on the side of an empty 10 gallon with an airstone under it to be honest. Then again I've never bred fish (and never will intentionally). I just want 3 of them to go with the 3 corys I have in the tank already (+ my Gourami and Oto cat), if I can hatch them all I'll probably keep them until they're a good size then sell them to my LFS for store credit and get some other stuff for my planted tank - I can't have over a 10 gallon aquarium unless I want to shell out hundreds for a pet deposit.

I'm pretty sure there are safe levels of H2O2 to dose. I do tons of reading and remember somebody mentioning that somewhere that I can't recall at the moment, so it is being done. The reason I mentioned it is because it would be a household remedy since you can't find a place to buy meth blue. It's just an alternative. Maybe darkening the tank with a towel to prevent light from getting in would be benenficial and doable as well.

Yes, a tank with sponge filter and heater are all you really need to hatch the eggs. The temp of your water is what will determine how quickly they will hatch. Water temps in the upper 70's will hatch in 3-4 days and temps in the lower 70's will hatch in 6-7 days, in my experience. This should be the least of your concerns. I find that I don't need to do daily partial water changes until the eggs hatch. It's after they start hatching is when the water changes become crucial.

In my hatching tank, I started with a brand new, unseeded filter mainly to provide highly oxygenated water with a good current. Some people choose to use airstones. I didn't mind it being unseeded, because I was doing water changes once or twice a day anyway, so the biological filter will figure itself out eventually.

Equally important is what are you going to feed them once the fry deplete their eggs sacs? I feed mine microworms and Hikari First Bites for the first few days then 1 day old live baby brine shrimp and crushed flake food after that. Once every couple of days you'll want to siphon out the uneaten food off the bottom at water change time then complete the water change.

Expect a 25-75% mortality rate from the hatchlings all along the way since this is your first batch. Mistakes get made and sometimes a water change or a feeding may get missed or underdone. If you do get a handful or two of survivors, eventually the 10 gallon tank will not be big enough, because they will get overcrowded. You will know they are overcrowded if you see torn or rotting fins and of course, deaths. Hopefully before this happens the juvies should be spread out across some of your other tanks for growout and/or graduated to a much larger tank.

If you haven't done so already, I recommend you read Ian Fuller's article on this site "So you want to breed Corys". He is The All Knowing Cory Man. His words are golden and I am just a peasant. LOL!

Since were going through a similar experience right now. Keep us posted here on your progress and I'll do the same so hopefully we can share experiences and both learn from this. This is my first batch of C. aeneus in 6 years, so I'm pretty rusty on them, but I have recently cut my teeth on C. paleatus and am having excellent success in a similar manner as the info I have been sharing with you. All of my eggs have some level of fungus, but I'm keeping my fingers crossed that some will hatch. They still look like they are developing on the inside.

These eggs were laid on 12/17/2012.

Do you think that your empty tank with eggs on the side looks so weird now?

Would you believe that of all of the places that I heard about using H2O2 was right here?!? LOL!

http://www.planetcatfish.com/forum/view ... =6&t=36016

Your setup looks so much better! Unfortunately I am between a rock and a hard place. I was called away to Portland, I leave tomorrow afternoon for 2 weeks - it is a 2 hour drive. This means I have to figure out what to do with the eggs and my fish.

Here's what I have already put in motion:
I trimmed the crap out of my planted aquarium, reduced my lights to 5.5 hours, and dosed only a minimum amount of trace (I will dose a minimum amount of macros in the morning to avoid unwanted rxns). I did a 70% water change and put in an Eheim auto feeder for my 3 Corys. I will be taking my Dwarf Gourami and Guppies with me, along with the eggs (it's risky, but I hopefully at least save a few). I have a cooler ready with heating pads. Tomorrow after work I will put my gourami in a bag and guppies in another bag filled with aquarium water and 2/3 with air from my air pump. I will place these in my insulated cooler with 2 heating pads attached to the top. I will scrape off the unhatched eggs (assuming some of them will hatch tomorrow, it will have been 3 days) and keep them in perware w/ water and oxygen and keep them in the cooler as well. If I have any hatchlings, I will try to catch them and place them in their own bag (the same as the other fish). I know this is asking for a high mortality rate, but again, I hope to save as many as I can. As soon as I get to my family's house they have spare tanks that they already have set up. I will try to acclimate and place my eggs/fry in that tank and hope for the best - The Gourami and guppies will all get their own tanks. I will be able to monitor/feed them as much as they need throughout the two weeks. If I get any survivors, I assume they can make the trip back a lot easier than the trip there. Let's hope for the best! This is definitely stressful, but it's the name of the game I guess.

Oh and I ended up dosing 4mL of H2O2 and it seems to have taken some of the fungus away (it was fun watching it react with the fungus and releasing the oxygen bubbles). I see black eyes on a lot of the eggs! Hopefully tomorrow turns out okay, I'll keep you all posted.

Wow, you are one dedicated hobbyist! I don't know if you could plan things out much better than you did. I wish you the best of luck and hope you get some eggs to hatch. I look forward to hearing your next report.

I found some H2O2 in the medicine cabinet and dumped a capful into my tank right before leaving for work this morning, so I didn't get to see the bubble display that you saw. Hopefully, I'll see less fungus when I get home. The methylene blue that I added a couple of days ago seems to have almost entirely faded away on it's own. I haven't done any water changes on the tank since adding the treatment. Still keeping my fingers crossed!

All 300 hatched!! They all made it on a 2 hour drive, too! They're swimming around in my 10 gallon. It's been 48 hours since they began hatching. I put a small amount of hikari first bites in the tank this morning and it looks like they didn't touch it. They're also not very active. Does this mean they're not done eating their yolk sac? They swim around but not very often. Also, is the excess food fine at the bottom of the tank? Should I just leave it there util it's eaten and them feed them after that?

I've had my first eggs hatch about a month and a half ago, and I fed them hikari just to get them used to dry food, but be sure to include some sort of microscopic live food, like infoursia found in java moss. Java moss will raise about 20-35 of your fry. I managed to raise 7 of my 10 peppered cory fry in a 1 gallon bucket, and they grew very slow, they didn't get more than a couple centimeter longer from when they hatched, but have developed all of their fins and even their coloration in these few months. Keep a little bit of debris to harbor infoursia, also, but keep up those water changes with that many fry. Good luck

You are so lucky especially under the travelling circumstances! Yes, you fed them too early. It will take about 3 days for them to deplete their egg sacs. Like Sino12 said, get some moss in there first, stay on top of daily water changes, then start feeding foods once the egg sacs are depleted. Siphon that food out or else it will foul the water.

I failed miserably! All of my 300 eggs fungused up. Lucky for me, mine started laying eggs again this morning while I was doing water changes, so I get a second chance. This time around, I ditched the sponge filter and moss for now, cleaned out the tank well, put an airstone in there, and immediately treated with Methylene Blue until the water was super blue. I also added a capful of H2O2. I collected about 100 eggs this time. We'll see what happens...

RobBob wrote:You are so lucky especially under the travelling circumstances! Yes, you fed them too early. It will take about 3 days for them to deplete their egg sacs. Like Sino12 said, get some moss in there first, stay on top of daily water changes, then start feeding foods once the egg sacs are depleted. Siphon that food out or else it will foul the water.

I failed miserably! All of my 300 eggs fungused up. Lucky for me, mine started laying eggs again this morning while I was doing water changes, so I get a second chance. This time around, I ditched the sponge filter and moss for now, cleaned out the tank well, put an airstone in there, and immediately treated with Methylene Blue until the water was super blue. I also added a capful of H2O2. I collected about 100 eggs this time. We'll see what happens...

Okay - I removed as much of the food as I could (it's almost impossible to remove it all with that many fry). Still not casualties, but they're mostly all swimming around the front and side glasses and messing around in the box filter. I guess this means it's time to feed them again! I can't find java moss. So instead I put a banana in a gallon bucket of water, I let it ferment for a few days but I'm not sure if this micro culture technique is going to work - the banana water doesn't seem to be cloudy. I will just try the first bites and wait until I see the banana water start to cloud and I will do some feeding trade offs. I can't find frozen bbs anywhere either. So I will just work with what I have. I will be adding some hiding places for them today and start on water changes (no ammonia readings yet, but I'll begin to be preemptive).

Sorry about your batch! I guess I just got lucky. I hope your eggs hatch this time. Keep me posted!

Unfortunately, my eggs didn't hatch again. I bought a new bottle of methylene blue for the next attempt. How is your batch doing?

You still out there?

Mine just laid eggs this morning, so here I go again. I bought a new bottle of Methylene Blue and started using it with this batch. I probably need to do daily water changes on the egg tank too. I'll re-read Ian's article again today.

Throwing in a handful of snails in with the hatched fry is another good way of taking care of some of the uneaten food that will inevitably end up on the tank bottom. They will also produce a bit of infusoria as well.

Hi, are the eggs actually viable? They almost all look white on the picture which can be a sign of non viable eggs which are much more prone to fungus. Picture might be misleading and eggs are not that white in reality but...

They look pretty good when they're collected. Mine are albino C. aeneus, so I think they're supposed to be whitish. They are not opaque white when collected.

I learned a trick from Ian Fuller when caught with fry and no microworms or other foods. Squeeze a very 'mature' sponge filter in with the fry. It might not look pretty but it is full of small critters for the fry. I have done it a couple of times and it works well. I can live with an ugly box or tank if the fry are surviving.

[quote="RobBob"]They look pretty good when they're collected. Mine are albino C. aeneus, so I think they're supposed to be whitish. They are not opaque white when collected.[/quote]

Albino C. aeneus are not white or whitish colored unless they are not fertile. They are an amber color like other Cory eggs.

Although I have no aeneus (albino or regular should not matter I think), I have venezuelanus which are almost the same species I'd agree - whitish eggs are not fertile. Sorry I have not followed this thread fully but how many fish you have? Have you actually seen them spawning? Might be you have a problem with a fish which don't produce fertile eggs.

should have added that first group of venezuelanus I had was only producing like 25% of fertile eggs. I thought it's common as I had two female fish spawning and four male. Now, I have their "kids" spawning after not even a year, maybe just one female spawning and have like 95% of fertile eggs. And you know right away which are fertile or non fertile. It's almost like you can see through the good ones but bad ones are really whitish.

RobBob wrote:You still out there?

Mine just laid eggs this morning, so here I go again. I bought a new bottle of Methylene Blue and started using it with this batch. I probably need to do daily water changes on the egg tank too. I'll re-read Ian's article again today.

Sorry about that! I've been fairly busy. I'm sorry to hear about your eggs!
I brought the now .5" Cory's home with me and I have about 100 who made it this far (I had some die off for this and that reason). Right now they're in a 10 gallon gravel/sand tank with a sponge filter and a piece of driftwood. I came home from vacation only to find 4 1" juvies in my planted tank I forgot about when I left! They're bigger because they have access to food day and night. They're thriving in there! That sparked me to throw in some java fern growth into the 10 gallon fry tank. I'm feeding them shrimp pellets and flakes right now as I haven't had time to do any brine shrimp hatching. They seem to be doing fine and are still growing, just not as fast as my juvies in the plated tank. After I pruned and did my big water change after the holiday I found about 70 new eggs yesterday. I don't have room to house these so they're sort've on their own in the planted tank :/. I have 3 mature cories, 4 juvies, and a dwarf gourami in my heavily planted 10 now. I can have anymore cories in there! I will probably just end up taking the eggs and putting them in the fry tank and seeing what happens.

I have collected eggs from Aeneus corys several times straight after they were laid and they are initially white. But the colour is a transparent type of white, not with a solid white in the center or solid white altogether. After 24 hours, the infertile ones are all white and the fertile turn cream/brownish colour. After another 24 hours all the infertile ones will be not only white but soft/mushy like.
If you are using medication to hatch the eggs, make sure it's completely removed from the water by the time the hatching starts as it can kill the small babies.

Here is my latest batch of aeneus cory eggs two hours after I transferred them to another tank and as you can see they are still white. There was probably nearly 100 eggs on the glass. About 40 corys hatched so nearly half of them were fertile and the babies are now several months old.

Thank you, Corycory for chiming in. I was pretty sure I could tell the difference between fertile and infertile eggs and that fertile eggs of the albino cory are translucent white. My C. paleatus are the same color and I had about 1 dozen hatch this morning.

I remember the mortality rate of the aeneus being around 75%, but I was less experienced at fish breeding at that time. My last few batches paleatus have only had about 30-40% mortality rate. I think I've gotten better at the feeding and water changes.

I have determined that the breeding group that I have is too old, because they are huge and all of the ~1000 eggs have been infertile. I am in the process of aquiring a new young breeding group of albino corys by picking up 1 cory a month from different lfs's.