I recently brought a kole tang it goes to one side of the aquarium and swims up and down the glass it's been four days now do I need to trade him or her lol for store credit ?
If the tang is eating and not getting "pinched" behind the head I would not worry too much. Prefering to feed off of the rocks is normal for a bristletooth tang. Offering seaweed would be a good way to supplement its diet.
I had a blue tang that use to do that but on the corners of my tank until I realized she was just eating the algae. It should be fine unless she has some discoloration of some sort. Just keep feeding and she'll get use to the tank.