Hi I have been having some problems with my angel fish i got it when it was maybe 2-3 inches. A while ago my angel got fin rot i got API Melfix and it went away know it i left on a trip for a week (had my family feed my fish) i came back and it had fin rot again so know if i mis put the Melfix for one day it loses half of its fin the next day dont know what to do. please Help!!!!!!!!!!!!!!!!!