A few days ago my tank inhabitant suddenly became very shy when I approached the tank and now they won'y even come to the surface to eat. I don't know what to do. Even the serpae tetras they are with won't come to the surface to eat. I know firemouths are supposed to be shy but this is rediculous. They just nervously dart around the tank when it comes time to feed. I have no clue what to do.