hmm, my mum bought a goldfish before, a very very large oranda. she didnt know no better and bought it form a fish store on one of her outings with my grandmother about 2 hours away from our home. the gold fish was infested with fish lice. i had to grab a few at a time. and plac ehim back in a container of water for a hour or so then remove several more. the fish lice moved around after i peeled them off, they were clear adn did look like bumps, like a jelly clear. untill i got them off then i noticed little brown speckles in the middle. might want to take your pictures to a pet store or something. it is a possibility thats what it is but not shure, i hope you can find out and let us know what it is.