I added seasalt to my fishes tank (just a tiny pintch) saturday night when I cleaned his tank out. I have been watching him since he has not been like himself. he will swim for a little while and then go to the bottom of the tank. He is spending most of his time at the bottom. I did add new marbles to his tank and the seasalt. So should I clean his tank out again? I have been treating him for finrot. I dont know what to do ! Help please!!