Hello all:
I have a black with red tips bala shark, which over two days developed a cloudy white growth extending over just its eyes. There does not seem to be anything wrong with the rest of its body. None of the other fish in the tank seem to have any problems or issues. It does seem to be losing it's ability to see, after a while it started running into things a bit more.

It was in a 55 gal, fairly densely planted tank, it is now floating in a mason jar with its own air supply. pH was 8.0 (I am trying to decrease the pH), nitrite 0 ppm, ammonia 0 ppm and nitrate 10 ppm. I am not supplementing with CO2. Nothing new has been added to the tank within the last week - 10 days. Prior to that period, I added a whole bunch of plants, shrimp, blue neons and hummingbird tetra. Though there hasn't been any problems until just now.

I can't tell from the forums if it's a bacteria or fungus. I don't want to use copper sulfate as it will wipe out my snails. Do I need to treat the whole tank? Can I just treat this fish?

It's tankmates include 15 olive nerite snails, 10+ assorted shrimp (ghost, Brazilian yellow belly, Rudolph red nose), 2 cory cats, 5 male guppys, 3 blue tetras, 6 rasboras, 1 elephant nose, 1 golden chinese algae eater, 1 hummingbird tetra, 1 peacock gudgoen, 1 molly, 4 otocinclus, 1 albino bala shark.

Thanks for any help. Cheers Jannell