75 gallon, 15" jag, fluval 405, 2 whisper 60s, weekly 75% water changes, mix of new life spectrum jumbo fish formula, hikari bio gold, hikari gold, tetra cichlid sticks, tetra cichlid color sticks, and tetra jumbomin. no attempted tankmates in years. i use carbon but havent changed it in a while and it is probably saturated with meds (from velvet that has now cleared up fine). i will be cleaning the fluval soon. i have heard so many causes and even more cures. any ideas? worst case i could use that 75 for lots of other things, but i like this guy and everywhere i post him everyone loves him. if it helps, it isnt the kind where it is a big gaping hole, its more like areas of light coloration and enlarging holes. so its not the kind where it looks like chunks have been scooped out. there is no discharge. only around head.