Normal. These fish sometimes will turn really red. Weird, orange or red patches are normal. The nipped fins is almost certainly from each other as they love to chase each other around and nip at each other.
When they come in from the wild they are always torn up pretty good. in the wild they shoal with other characins and during a feeding frenzy whatever is in the way is food, including each others fins lol.
83 degrees is what I consider a 'hot' tank. Not many species need water that warm. the fish in the your
photos, the silver dollars and parrots will be good in low to mid 70s. 76-77 would be ideal.