you can teach those things quite easily to eat live gold fish out of your hand. They will jump up out of tank to get them. Did he kill all your other fish? They will also jump out of tank if they feel crowded. When pools dry up in the amazon they jump form one pool to the next (or so I have readis the speculation on why they often end up on the floor if in a crowded tank. Cool fish though. We fed one a huge live lizard once it could only get the head and front legs in it's mouth it swam around for a day or two with the back end hanging out. We fed them crickets, cockroaches, spiders, those fish will eat about anything.