This is one of mine in the Uk

Congratulations I left my Oto fry in the main tank as there is plenty of algae for them, they also love zucchini & are all over it when it's put in.

You wouldn't post as you think it's cruel yet you flushed them!?! Flushing is a horrible thing to do to fish they'll have suffered a painful lingering death, shame on you

Most Lfs I've seen them in label them as black Venezuelans as that's what their importers name them as unfortunately

They were developed in Germany but since then have been extensively bred in the Czech Republic, there is a post by Ian Fuller on this thread explaining it.
http://www.planetcatfish.com/forum/viewtopic.php?f=6&t=32934&p=219184&hilit=The+true+all+black+cory#p219184
We in the Uk have the same problem ...

Aad is right, they're C.schultzei sp. black, a man made colour variety developed in Germany, they're not found in the wild