Breeding Corydoras adolfoi

by Mona Opland

y group of 8 wild caught C. adolfoi spawned for the first time in my tank only 3 weeks after purchasing them. In those 3 weeks, I provided lots of nutritous and varied food (frozen) such as red mosq. larvae, freezedried tubifex, sinking Hikari Cory food tablets, frozen brine shrimps and so on, JBL Krill flake food now and then as well. I tried to not give the same food two days in a row for variety.


Corydoras adolfoi = pair = Male (left), female (right)

The tank is not very brightly lit, only one light tube of that kind you use for plants (kind of pinkish light in them). They seem to feel safest when the light is not to bright, roots for cover, and a lot of fast growing plants and sand at the bottom as substrate.


Corydoras adolfoi = pair = note the silver ring around eyes


I usually change 10% of the water each or every second day, and kept the ph at 6.7. The hardness isn't much to talk about in my tap water, kH is 1 and gH is 1 or 2. Very soft in other words.

After the first spawning there has been little efforts made to make them spawn again... they do it anyway :)

They spawn almost constantly, and have been doing so for 7 months now. Only a short break for 3 weeks in February, but then they started again and have spawned EVERY week since then. I have raised some of the fry, and currently I have about 20 about 5 and 6 months old. I stopped picking out the eggs before the summer started, since vacation time was coming up.

The adults usually eat the eggs stuck on the glass, but the ones in the java moss they seem to leave alone. It's always only one breeding pair at the time (one female and one male), the rest of the group does not participate. The spawning pair themselves never eat the eggs, but the rest will if given the chance, so I usually sit guard and pick the eggs out one by one as they lay them:-) (what a job...)


Corydoras adolfoi = the eyes prier to spawning


My best tip for hatching the eggs is to take a filter stocking, stuff it with peat, and leave it in the hatching container. So far, no eggs have fungused with this method, but remember to change the water a day before hatching! The water gets very acid with the peat, and it's best to change it before hatching since it's much more difficult to make any changes at all AFTER the fry have emerged. They can die even if the temperature changes as little as 2 degrees celsius.. in other words, very sensitive fry .

I feed my fry with freshly hatched brine shrimps for the first four to five weeks, then I slowly introduce other foods. C. adolfoi can be hard to raise if you don't feed them newly hatched brine shrimp because they don't touch other foods, in my experience. they just die of starvation. Keep the tank CLEAN, daily water changes of 95%. Sounds much, but it does the trick. Remember to keep both temperature and P.h at the same on the new water as the water in the tank!. I also clean the tank every day for the first weeks, by scrubbing it in hot water. Much work, but the survival rate is high :)

My first brood of C. adolfoi had a 100% survival rate with these methods :-) (this was my first try ever at breeding Corys...) I picked out 11 eggs, 9 of them hatched, and all 9 are now happily swimming around in one of my tanks. They are 6 months old.

Click on the thumbnails below for a full image of the frys growing progress.


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1 day old, still with yolk sac

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8 days old

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11 days old

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3 weeks old

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One month old fry

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7 weeks old

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8 weeks old

I would like to point out some interesting fact regarding these particular photographs. They all show the adolfoi in spawning mode. NOTE the silver ring around their eyes! Normally, their eyes are totally black with no silver ring. But on the day they are planning to spawn, this silver light ring shows up in their eyes. Interesting, isn’t it?

The first 2 photos shows this phenomenon most clearly, as the pair was actively spawning right at that moment. I have taken several photos of this, and all the pictures show different degress of that silver ring around the eye center.


6½ months old

Images by author


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