Hi, I have a sick goldfish in my sons fish tank. It is a white goldfish, some of its scales have come off and it has what looks like blood showing through his scales all over his body. It is a small tank about about 60cm x 50cm. It has a filter in and we do 25% water change every two weeks and it has two other fish in. Any help would be greatly appreciated. Thanks. Sorry tried to post a picture, but it would not work.