A lot of those Amazon fish will go insane when lights are turned on. They naturally live under dense trees and murky water, so little light gets through. They are adapted for darkness. When light goes on, it hurts their eyes same as it would yours. If you think oscars are bad try serrasalmids (piranhas, silver dollars, pacus). They don’t have contractile pupils so they go insane.Oh wow he healed up great. Turned on the lights when they were asleep an he went crazy. Never ever gonna do that again. Trying to get a photo of the pbass
Thanks soo much everyone, glad it wasn't a fungus or parasiteMy peacocks get that all the time probably from a fight or scrape on filter or decor. Will look better than before it happened in about 2-3 days