if you have removed his hiding spot and he seems to be lookin for something ,.. id put a stop to it. Put the rock back in and keep him happy. Mine escaped through a ,... .25" hole and he was 18" or so. Its not worth it to see him as you will as he grows
and the breathing, its somewhat normal as they look they are trying to swallow the water to breathe, as long as it is not real fast pace