Noticed one of my clowns have developed what I thought was brook, but I’m thinking now may be something else. Had them about two months now, tank is fully cycled. Reading No ammonia. Noticed horizontal lines on both sides close to his spine. Doesn’t look slimy or puffy, could this just be aggression from another fish? Looks similar on both sides. He seems pretty normal other than that. They like the bottom corner near the heater, seem to be eating normally