I have a pair of Cyrtocara Moori housed in a 180 litre tank (they are the only occupants). One of the 2 has some marks on its dorsal fin...I cannot tell if it slightly furry or if the fish has damaged its fin on some rock. I am quite worried as if it is fin rot or fungus will it spread? I have added some anti fin rot drops to the tank but wanted to know if this species are prone ot abrasions or should I fear the worst?