How many should I put in a group? I'm setting up a 20gallon soon and I was going to move my Danios into it at first (if there was something drastically wrong with it they wouldn't die... better to be safe than sorry, even if the results come out safe) then put in some Pygmy Corydoras and 4 or so Glass Catfish. It would be heavily planted, too. How do glass cats like plants? Glass cats will eat flakes and live food, too, right? I would typically use this as a breeding tank as well - I could just acclimate the fish to my main tank and leave the pygmy corydoras, right?