The wild types are actaully not that easy to find sometimes need to search a bit, guess the leucistics and albinos are more popular. The place where I got him had about a dozen of them in one tank there were two like him with greenish wild colour about 5 black ones but they were all pretty skinny and were attacking each other. The two greenish ones looked the best out of all even thouhg they were the smallest. They were feeding them tubifex worms which I think is not enouhg for them this little guy when I brought him home ate about 8 small earthworms so yeah he was really peckish.
The big guy did nip the little one but and soon as they bite they bolt so quick so little damage is done, and the little one spooked the yellow one when he entreed the pipe. They seem to keep quite seperate its almost as if they have defined some type of territory, the yellow one stays in the pot while the other one roams the tank.