i've noticed it on my yellow tang lately, its not that bad, just a little around the eyes, but i definitely don't like for any of my animals to have anything going wrong. I feed it well with green seaweed soaked in garlic, and i've tested for loose current and there isn't any. The only thing i could think it could be is my pH, which is 8.6, and i've been trying for a month to get that down