Injured Jack Dempsy gets fin pulled off in a fight?

i also have a cichlid tank with both types of fish in it. I've noticed when one of my fish is going to die it hangs around the top corner of the tank near the power heads. also the fins should grow back. my fish fight alot. ive seen firemouths tail basically complety gone but now its full again. im not a expert by anymeans but this is just in my own experience.