Finally realizing why my guppies have non stop tail rot. There is an albino koi guppy who clearly cannot see well. He spends all day following around "fancy" guppies with long tails and nipping at them. There are 6 guppies but he seems to really only nip at 1 in particular at a time. He nipped at 1 for months who recently died, I suspect tapeworms or bad genetics. The stress from non stop nipping didn't help though. Now he's chosen another one who he follows around all day, giving him terrible fin rot Besides moving him into his own little tank, what else can I do?