My littlest goldfish died! I have no idea how he died. But the creepy thing about this is that his tail fin, dorsal fin, and mouth had been torn off! I don’t know if this was one of my fish who did it, or if he got stuck to the filter? I have 3 other goldfish, 5 dojo loaches (3 of them are up to 10 inches), and 2 small Clown plecos. Please help! I don’t want any of my other fish to die if I have a murderer in my tank!