We just lost our beautiful huge goldfish, we've had him for about 12 years. He was in a 55 gallon tank with another smaller goldfish, a dojo loach, and a suckermouth catfish. No heater, no bubbler, but two large filter pumps. The four of them have been together for years.We do a partial water change about every ten days to two weeks, and add water conditioner. change the filters about every month to six weeks. Feed once a day. We have well water. I know it's high nitrate but there's nothing I can really do about it, it's well water. I just fed them yesterday and he seemed fine; he was eating. I last did a partial water change and cleaned their tank, and changed the filters, May 11. The water was hard, we needed softener salt, but it wasn't discolored or drastically hard. They have had the same gravel in their tank for a long time, but I always vacuum the gravel. I'm just wondering if all the rain we have had might have had something to do with it, maybe there were more nitrates or nitrates or some toxin in the water from all the rain? WE have had a lot, and I heard recently that all the rain this year was affecting hay quality, leaching out nutrients in the hay. But if that were the case, why would it take so long? It's sad, because he was very tame, he would eat out of my hand...and the other fish acted distressed at their buddy lying in there upside down. Just wondering if I should do anything now to try and protect the other fish, or if anyone has any thoughts about this?