No no no, no Melafix. >.< If you have to use ANYTHING with a 'Fix' at the end of the name, use Bettafix. Melafix can harm the labrynth organ which allows them to breathe. They're surface-breathing fish. Don't add any medication to his water yet, just aquarium salt... If it doesn't look better tomorrow... Bettafix is a last resort. However, for the fin rot I'm about to treat my rescue for, I'm using Maracyn I. Safer than Bettafix/Melafix, and I know an excellent new way to dose Maracyn for smaller tanks.