I have a 7ish inch male polleni, that two weeks ago had a blister like growth on his gills, its was small and I added some salt and it was gone the next day. Now he is acting normal except, breathing heavily, I added a powerhead and a large air pump and two stones. He was always jet black ever since I had him and now he loses his color a lot. He eats fine no clamped fins and everyone else in the tank is fine. I have two filters turning the water 5 times an hour, I do 30-50% water changes every 3-4 days religiously. Its a 135 lightly stocked with a few other small fish around 3-4 inches, there is nothing visibly wrong with his gills either? Ive been in the hobby for many years and never seen or had to deal with anything with gills.The pic is from this morning when he was colored and acting "normal" Any ideas?