Nothing else is in the tank because I caught him and separated him from my actual tank. He's in a 2.5 gallon eclipse with a couple pieces of live rock. I had a few fish in my actual tank that disappeared mysteriously, and I'm sure he's the reason. But right now he has nothing but a few pieces of rock. He seems to be happy, and snatches up the invertebrate pellets really fast. I guess if I ever have any fish I don't want anymore I can just give them to him!
(j.k.). I actually noticed him when I looked really closely at a yellow polyp rock that started looking very sparse with it's corals. I actually caught him in the act of grabbing a polyp. He's a disaster to a tank, but so cute now that he's isolated!