I have a pleco that is just staying still on his rock and not moving. He doesn't even respond when a net is inserted into the tank. Usually when a net is insert in the tank he goes berserk and takes off. But today you can nugde him with the net and he doesn't do anything. I have no idea what is going on with it. It was fine last night before I went to bed. My other fish are fine. I have daninos and they are swimming around no problem. Please help 
