To me it looks like nipped fins. I see you're keeping some Malawis in there as well, they are not supposed to be together with Frontosas. Not only that they're coming from different biotopes, but their feeding behaviour is so different as well. Frontosas are not as competitive for food or as active as Malawi Cichlids.
I strongly recommend you do a Tanganyikan setup... Frontosa and other compatible fish.
I strongly recommend you do a Tanganyikan setup... Frontosa and other compatible fish.