All the fish still eat, but it appears to be spreading to the bodies of some of the other fish now as well. Water is fine I checked that, no ammonia, nitrite and roughly 30ppm nitrate. Sucks to have to treat a tank this large...from everything I can read and compaare it to it does appear to be bacterial in nature so going to go buy some melafix and see if that helps. Just finished doing a 75% water change anyway which was quite fun :/