Hi, so I have a pair of clowns and they have been fine up til now and even sleep with each other. My black clownfish grabbed onto my other ones fin and would not let go for a good 20 seconds. It keeps nipping at him now as well. I noticed that the bullied clown has developed a pale lip and I'm not sure what to do. They have always been fine and were the first fish to add to the tank. I made sure the black one was bigger so that it lowered the chance of two males. What should I do?