I don't think I like reading that these fish get aggressive as they age. It may be the reason my panda cories (3) died suddenly. Why don't the pet stores tell you this info? And 20 inches?? I'm in trouble if that's the case. I'm sorry I didn't research it better before I bought him b/c every now and then I see him "go after" another fish in my tank but it seems quick so I don't think much of it until I read this info. Mine is almost 4 inches and doesn't eat the wafers either and I've had him 7 months now. He seems to eat food that falls to the floor. I'm going to keep a close eye on him now to make sure he isn't causing too much trouble in my tank. It's a shame b/c they are cool looking.