Tang having a lot of problems

[Puffer22]

Lately i've been very worried about our hippo tang. We've had him about 2 years, no problems until fairly recently.
About a month ago - It all started with him getting stuck to our powerheads. Usually a fin would get caught and he couldn't escape, leaving him to hang there till one of us gets home to unplug it and free him. He seemed fine the first couple times and then we purchased some cross stitch plastic (a fine mesh) and covered the big gaps in the powerheads with those. He hasn't gotten stuck since.
About 2-3 weeks ago - No longer getting 'stuck' to powerheads but he's taken to sliding into our monticap upside down. He hangs there just wavering in the breeze and usually only comes out to eat, when he does. It's like he's dead and lodges himself in there. He can get out just fine. Once he scratched himself pretty well, white scratches all over his body on one side. We also notice that occasionally he comes out for a lap then it's right back in. At feeding time, if he bumps into anything, he freezes. He'll get stuck in that locked up frozen position for up to 30 seconds or so.
This week - He's been hanging in his monticap spot all day every day, still feeds pretty good but he looks thin. Sometimes he'll come out to only put his nose in a corner and sit there like that for hours.
Today - Came home to find him wedged between layers of monticap. Not sure how he got in there from the opposite direction. We break off a branch to free him and he sits there for a minute then scoots free. This time the damage is bad. His entire left eye is completely cloudy. Not sure if he's scratched it badly, but the body has scratches on that side too. He had problems feeding today, didn't want to come out of the monticap, just saw a yellow tail hanging out. When he noticed the clowns were going nuts, he came out but it was very hard for him to feed it seems. He can't see well or at all out of that left eye.
Is there anything we can do at this point? We've had him for years and really dont' want to lose him but he can't be happy. Water parameters are fine, no problems whatsoever. He's only about 4" long. We have 2 clowns as well and they are just fine. Corals are happy, other than our toadstool, it has a flatworm issue at the moment. Anyone know what to do?

 

[Gwynhidwy]

It sounds like it might be stress behavior causing him to hide more than he normally would. What size of tank is he in? Are the two clowns the only other fish? Are there any invertebrates that could be bothering him? Perhaps a hitchhiker like a mantis shrimp or crab? The last one's not terribly likely, but trying to give possible ideas. What are you feeding him and how often?

It is very normal for hippo tangs to wedge themselves in between things when they are resting. It is also pretty normal for them to have scarring from this behavior. They don't normally spend most of their time hiding like you are describing though, usually only at night and when stressed. It would probably be best not to try to remove him when he hides.

 

[Puffer22]

He's small right now, in a 75 with a 150 being prepped for him in the garage. Only other fish are 2 clowns. I don't think any inverts are bothering him.... we only have some small blue leg hermits and one large scarlet..and a handful of snails.
No hitchhikers evident after we removed that stupid whelk about 6 months ago. 90% of his time is hiding in the monticap but he does come out to feed and eats. He went nuts over nori yesterday. He also just sits with his face in the corner and leans to one side some..starts to float up..then he skitters off to the monti again. He makes the occasional lap around the tank but doesn't stay out long at all.
We didnt' remove him from hiding..he was really stuck. His usual position is face first into the shelves of our monti. Somehow he wiggled around and he was face out. Usually opening the lid prompts him to come up and see if it's feeding time or make a lap. He didnt' move. He couldn't even flap one fin while he was stuck. We broke a piece off to let him out and he could have stayed put, but he took off after a minute. He has tons of hiding spots.