Help! I have a very old goldfish that lives in my pond in the summer, and in an inside tank in the winter. For many years he had a buddy, but that fish was killed last summer. Since then I have brought home innumerable new little companions to keep him company, but none of them lasts more than a couple of months. They are happy and healthy right up until the time I find them dead - no signs of illness or injury. What is going on? The lady at the fish store says that my old guy is too big and must be roughing up the new little ones, but I don't think that is the reason, as I never have seen him being a bully to the others. What else could be the reason? They always look perfect when I find them (fins are complete, no lesions), just dead. It's very sad - I'm afraid to bring anyone else home!