It actually looks like the beginnings of Epistylis which is a parasite that lives on the fish but feeds on the bacteria on the fish ( versus say Ick which feeds on the fish itself). Are your other fish in danger? YES, because once this parasite is in the water, it will find a host to attach to.Oh shoot 2 weeks ago 3 baby Cory cats . If that’s the case are my other clown loaches going to be in trouble and if yes, what should I do? Cause I know you just can’t put any medicine in there because the loaches are skin and not scale.