hlle.lateral line erosion

I have a 10 gallon SW FOWLR (for now, bc lighting is inadequate for reefing) about 10 lbs of live rock. 50W Heater Fluval 30 filter ( i have removed the active carbon ) live sand substrate T8 reef sun 50/50 bulb no skimmer no airstone 1 blue/green chromes 1 ocellaris clown 1 red leg cortes...

Hey guys, I'm in need of some help. I just picked up a 10-12" Orange Tail Emperor Angel (Xmas Islands). He was in my friends tank which is a 300. He has HLLE and hole in the head extremely bad. I have cured this in the past with smaller fish that weren't adults. Any chance this will go away...