There's this thing about the Glass Catfish, though: no matter how well you feed and take care of it, a glass catfish will die if it isn't around enough Glass Catfish. More than food, they need love.
At the aquarium, my wonderful friend zanawake pointed out that the Glass Catfish have their own section on Craigslist to meet each other. Glass Catfish seeks companion. Three Glass Catfish need a fourth for bridge. Nine Glass Catfish need a tenth for a minyan.
I can't see the links, though. They're transparent too.