yesterday i noticed my senegal floating at the top of the tank. as he tried to swim down his rear half tried to stay floating. at first i figured it was a swim bladder problem and was expecting him to be dead this morning or still floating but to my dismay, he was chilling at the bottom. this has happened one other time before with him. could it still be a swim bladder problem, could he be eating too much, or maybe something else. water parameters are good temp is 76-78, just did a water change tuesday