yeah sounds like fighting damage.they should be fine, that fish could be constipated, or if there is an internal parisite, you should at the very least raise temp slowly maybe 85. watch them to see how they react, i also always added aquarium salt to my water changes, just a little. knock on would i havn't had trouble with fish diseases in a long time, sometimes hard to believe but if the fish is stressed because of tank mates or water parameters could add to the problem