yellow tang hiding in the rock?

i dont know why mine does the same thing

I don't know a lot about tangs, but I have one who can act pretty weird sometimes too. He is really personable and loves being out in the front though.

A lot will depend on the temperment of the tang. Some are very bold and always in the open, others like to have someplace to duck out of sight. Not a problem, as long as the fish is eating well and healthy.

try feeding them sea grapes mine comes right out and eats them and usually stays out for a while.

If the tank size is wrong this will make them unhappy. You didnt mention the size of the tank but if its under 100 gallons then it really shold not have a tang in it
If the tank is large enough to house one then how long have you had it and what o ther fish are with it? My tang is the absolute opposite, my emperor is on show at all times and is the boss of the tank even though he by no means the largest in the tank. tangs have very different temperements as has already been mentioned. More info on the tank, perameters and tankmates would be helpful.

well 100 gallons is a lot of room for a yellow tang... 75 would be a minimum... right now I have mine in a 55 and he will be one of the last editions to the 400 gallon I will be getting in a few months

With the exception of perhaps a kole tang, no tang should be in less than 100 gallons. Yellow tangs and purple tangs are no different. they are open reef swimmers and cruise for miles each day. They also grow far larger than most people realise. (even i was suprised wheni saw a Black tang 9 inches across in a local aquarium)