alright so i have a small goldfish that i bought around december and it has gotten these black/green spots on its head and the end of his tail is like gone. he can still move is pretty sluggish. i also have 3 other goldfish in the 20 gallon tank.
P.S. should i move it to another, smaller tank to avoid it spreading?
P.S. should i move it to another, smaller tank to avoid it spreading?