help!!

[balistidae]

I have had an undulate for about 6 days and he has been behind the rocks the entire time. I caught a glimpse of him today and i noticed he has sort of a "bubble" over one of his eyes. What is this and how would i treat it. Would this be why he has been hiding??thanks!!

 

[beth]

Sounds like popeye. This could be an injury resulting from netting the fish. It could have also been initially an injury which is now an infection. Could you tell if the fish's eye is cloudy? Is the fish eating?
How is he doing besides the eye? Breathing normally? What type tank do you have him in?