Blue tang acting weird and different

[Reefer2001]

For the first time my blue tang acted weird today. He always was swimming arround very happy with no problems. Today i was watching my aquarium, and did not see my blue tang. I was scared becuase i could not find him. There was only 1 place left. Under my rock. The place my stone cleaner (don't know the name) has it's own made up place to hide. It's a big fish that rules my aquarium and scared off my 2 clown fishes. The first day my blue tang was not scared of my big fish wich made me confused. My blue tang always hangs out with my clown fish, still from day 1.

Anyway when i was looking for my blue tang i picked up my rock and found my blue tang very deep inside (under the rock) laying down and not moving much. I tought the big stone cleaning fish hurt him but he was just cool with him being in his home (he never does that to my clown fish). But now i worry because my blue tang keeps staying in de corner of my filter on the bottom of the aquarium. But now it's on the top corner as if he is dead. I can still see him breathing. But he doesn't move. After hours i checked back and still same place (it's night time now)

Here's a pic of the (rock cleaner big fish)
And a pic of my blue tang right now.

 

[blaxsun]

Why exactly is he in the filter?

 

[Uzidaisies]

The fish is probably sick, but without a good picture of the fish and/or more detail such as tank parameters it’s going to be hard to diagnose.

 

[Reefer2001]

He looks happy now that i'm watching from far away. As soon as i get close they get scared and go under the rock, but that is not the case when someone else comes. We are renovating and lately there is a lot of loud noise and a litle dust here and there. I think he is not sick but just scared.