What is a goldfish with no fins?

It is very badly damaged and will probably die.

-----improved answer ----

that's actually incorrect, unless there are signs that there was a fin to begin with, in which case it is probably fin rot... but if you are talking about those goldfish that swim super awkward and have no fins on their back, then you are talking about a celestial goldfish. some bubble eyed goldfish also come with no fins.