The past summer, on impulse, we added 4 gold feeder fish to our existing 2 grown, 1 mostly grown, family. They've grown nicely to a good 7'' to 8' excluding tails. In any event, this past April one of them vanished. We assumed it was likely a heron as while we've had raccoons in the yard they've never shown any interest int he fish. Oddly enough, about 12 days later it reappeared but with a chunk missing from it's side. Nasty looking wound that as healed nicely but wound or no wound it obviously hadn't been taken by a heron. Two weeks ago and second smaller fish vanished only to reappear 9 days later also with a chunk missing. It was rather disoriented...tail frantically swishing back and forth and, for the most part, swimming with it's head down. Within twenty 24 hours it was swimming as normal. We've had water snakes eat small bull frogs and we have skinks but neither of them are good candidates for what's happened. Any ideas?