We have had a goldfish that we won at a state fair for the past 4 years. He has gotten quite large, and has always been very healthy. He has outlived 3 or 4 tank mates that we have gotten him, and is now alone. Over the past few weeks, he has been developing a problem. First, we noticed blood in his scales and going down into his tail. (not dripping out of him, just in his scales). I cleaned the tank out, thinking maybe there was something in there effecting him. Then the top portion of his tail disintegrated over a few days. Now the same thing is happening to his lower part of the tail. He also has a large white-ish area where the end of his body meets his tail. His upper and lower fins dont seem to be moving a lot, but the two on the sides are constantly moving. He is staying up towards the top of the tank all day long. Not floating like he is ill , but treading water. Any ideas?