Looks like fin rot. I have a 90 gallon well- established tank, fine for over a year. 4 pictus cats were added last about 6 months ago and they grew like gang busters. I feel like maybe the vampire is not getting enough food because they are such maniacs. I love this vampire - the pictus are cool but I'll rehome them rather than lose the vampire... Do you think the 4 pictus are most likely the issue?