My fave boy who had issues like this about a year ago now again has some fin issues- not as bad as before-
He's about 2.5 yo, in 10G filtered planted tank, alone. Water params are fine. Very spirited boy, gets 2-4 pellets 1x/day, lots of H2O changes, he had finrot 1yr ago and it took 4 months of dif treatment and water changes until he showed new growth.
Now it is not as bad- so I started with H2O changes and AQ salt for 10 days, it got worse. So started maracyn 1 and 2- then I saw some white areas, so added moroxy- today is day 5 of moroxy (7 days since the last H2O change) and he is not worse but not better.
Tomorrow I will do water change in his tank to get him out of this chemical milieu, and I will likely do AQ salt still, BUT I am considering whether I should do kanamycin and another afungal) both of which I have- after this water change???