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First off I will tell you how I care for all my corys, They all have java moss, sand, and a sponge filter. Temp is around 79. I feed a special blend of pellets, flakes and frozen blood worms (once a week on the blood worms). I have 6 Albino Corys and 9 Black Corydoras in one tank, I have 6 or 7 Julli in another tank, I have 5 or 6 Sterbia in another, I have 6 Peppered in another tank and 5 Bronze in another. The problem I am having is that none for the Jullie, Sterbia and the Black Cory have never spawned. The albino and the peppered have only spawned once and then stopped.The bronze corys spawns all the time. I have at least 1 female of the albino and the black that are huge but have never laid eggs. I dont see how they can get any bigger, they look like they are going to bust. So I come to the experts to try and get help and some must needed advise. What am I doing wrong or what am I not doing to please them so they will spawn. All help and advise and suggestions is greatly appreciated. Thank you so much.

Welcome!
While I am not an expert on Corys, please add info about water quality and water change/clean frequency. This information is key to solving your question.

We do weekly water changes and cleaning, all water conditions are in the normal range with the PH just alittle higher then suggested.

I have a few suggestions.

1. Raise the temperature for the sterbai up to 82. Mine liked a warmer temperature.

2. Reduce the group size to 2M and 1F. Too many fish in the tank will discourage spawning (or the extras may just be eating the eggs).

3. Feed live blackworms. Particularly for a few days before a cold front comes through.

4. Do a large water change with cooler water the day before a cold front comes through.

This usually works for me.

Andy

thank you for the suggestions Andy

Hi debbeesm23,

debbeesm23 wrote:They all have java moss, sand, and a sponge filter.The problem I am having is that none for the Jullie, Sterbia and the Black Cory have never spawned. The albino and the peppered have only spawned once and then stopped.The bronze corys spawns all the time.

Different species of corys like to lay their eggs on different surfaces in the tank. My albino and bronze corys almost always lay most of their eggs on glass, with some on wide plant leaves too. By contrast, my trilineatus (often mistaken for julii; so are you sure yours are julii?) prefer to lay their eggs on surfaces like plant leaves, plant roots, and decorations; very few of their eggs are laid on the aquarium glass. I can't speak for sterbai or black corys, but maybe your "julii" don't like the spawning surfaces you've provided; if all you have in the tanks are java moss and a sponge filter, you might not have the right surfaces for egg laying for each species.

Moreover, corys differ in how many eggs they lay in one place. My bronze and albinos lay most of their eggs in just a few specific areas, with many eggs attached close together and highly visible; but my trilineatus typically only lay a few eggs at a time in any one place - the eggs are all over the tank. I suppose it's possible that your "julii" might have spawned and you just didn't find the eggs because they are scattered around in tiny groups, relatively hard to find.

The other thing I find important, which is related to the water changes already mentioned by Andy, is that my albinos and bronzes really like to lay their eggs on the glass near places of high water flow (like under the outflow from my external power filter). So if all you have is a sponge filter, maybe it's not providing sufficient stimulation to spawn. You might get additional spawning stimulated by creating a stronger, directed water current.

debbeesm23 wrote:I have at least 1 female of the albino and the black that are huge but have never laid eggs. I dont see how they can get any bigger, they look like they are going to bust.

Obviously, if your corys have already spawned, you probably have both males and females (but I have had times where lonely females deposited eggs when there were no males around to fertilize... I don't know why, but it can happen). And given your group sizes, I would expect you to have both sexes for each species. But are you sure you have males and females for all your species?

Cheers, Eric

Thank you, Eric. I am definitively going to do more research.

I can only give advice about the sterbai. I have 3 sterbai, and a big bunch of aeneus corys.

The sterbai don't spawn on the glass. They used to love to spawn on the floating plants I had some time ago. It was impossible to find the eggs when they spawned in the floaters but it was funny watching how the female would shoot up and lay the eggs. When I removed the floaters, they started loving my anubias. I had lots of plants at one time and they still just spawned on the anubias and nothing else. The female would lay one and even rarely two eggs max on each leaf underneath after all three of the sterbai fuss around the plant until one of the males prevails. I can always find eggs under the leaves afterwards all over the plants.

So maybe, put some floaters in the sterbai tank

I don't know what to advise otherwise. If the fish are healthy and comfy they start spawning early or later without much fuss. But if you want to trigger them to spawn right now, you may have to do something about it I suppose.

Corycory wrote:So maybe, put some floaters in the sterbai tank

Or try adding spawning mops to your tanks; they might work too.

debbeesm23: read this article about "Dry and Rainy Seasons in the Tank" from aquarticles.com written by Kristian Adolfsson.
Emulating the Dry and Rainy Seasons is the key to hard species to bred.
http://www.aquarticles.com/articles/bre ... asons.html

PabloG wrote:debbeesm23: read this article about "Dry and Rainy Seasons in the Tank" from aquarticles.com written by Kristian Adolfsson.
Emulating the Dry and Rainy Seasons is the key to hard species to bred.
http://www.aquarticles.com/articles/bre ... asons.html

The easy way to spawn them/emulating "dry and rainy season" is to leave the fish without a water change for a couple of months with minimal feeding. Then do a large water change and start fattening them up. I just didn't want advising this as its actually unhealthy to the fish in such a low volume of water.

If it were me, and I am not breeding for commercial purposes, I'd just leave them get on with life. If they appear skittish, like hiding a lot and running away when someone is near the tank, they are just not happy and an improvement of the conditions is needed. That may involve improvement of the water conditions themselves, overcrowding, change of tank mates, or more hiding places, not fiddling with the tank daily and spooking the fish, not letting your dog lick the glass , not letting your kids tapping on the glass, etc...different things.

Corycory: Off course. I'm not doing this with my corys. It is to read and take a dimension on the odds to work on hard to breed species.

Yes, sorry PabloG. There's lots of good info in that link for other approaches. It's just that when I hear rainy and dry season, no water changes come to mind, lol.

Today it just crossed my mind about water splashing on the surface.
I keep my two bunches of corys in large tanks which are well overfiltered but they are open top, meaning the water evaporates quite fast each week and just before a water change the spraybars are actually splashing at the water surface from above.

I change the water on Fridays. I have always wondered why my corys spawn just prior to the water change, rather than after the water change. But could this be due to the splashing spraybars, meaning simulating rain?

It's worth a try giving them some "rainy" conditions in an easy way like this.

So interesting. Which cory species exhibits this behavior?

Gold laser, sterbai, albino aeneus are the ones I have.