Breeding Corydoras

The Bizarre Truth

The question has always been just how did the male’s sperm fertilise the eggs? Most watchers assumed it happened by the female taking sperm into her mouth and then placing it on the spawning site before pushing her eggs on to it. The truth of it, however, is far more remarkable. By using a marker dye our biologists found that the female did indeed stimulate the male to release his sperm when they were in the "T" position.

What happened next was more interesting. Having taken the sperm into her mouth she swallowed it! A few minutes later the sperm came out of her vent followed by a batch of eggs being released into the pelvic fin pouch. With the sperm the researchers’ dye was also released so they could see it had actually passed right through the females gut and come out the other end!

Proof positive of how Corydoras aneaus (the test subjects) breed.

Aquarists can now fill in the gaps because we have been observing many different species of Corydoras breed and so far every single one of them forms the "T" position during their mating sequence. So do the closely related Aspidoras and Brochis.

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