u/GlowingTrashPanda

I checked on the main tank earlier today to find my smaller male looking skinnier than normal, breathing really heavy, and with really reddened gills and what look like sores on his lips and by one eye. I checked the water quality with the API master test kit and everything came back as expected for a 5 year old tank in South Florida (Ammonia: 0ppm; Nitrite: 0ppm; Nitrate: between 5-10ppm; pH: 8.2). I still did a ~30% water change. I have done a few 10 sec methylene blue dips (8ml of Kordons in one gallon of tank water). I then moved him to the snail tank to quarantine him from the others. Is there anything else I should do?