Are they like red streaks or more like the beginnings of ulcers? What other fish are in with him and how large is the tank.
If it's the former, it's septicemia (blood poisoning) usualy the result of bad water quality and stress though it's occasionaly linked to infections as well. Do lots of water changes and test your water parameters. If it's the latter, it could be a number of things. How is he behaving?
They look like.. a rash, like dots, pimples I guess you could say. He's in a heavily planted five gallon by himself and the water is changed biweekly. He's his normal porky, surly self. Second he sees something he'll race toward it and lunge. He's acting and behaving normal other than the semi clamped fins and the red dots.
Red spots on skin can be caused by:
Regarding the small red dot, small pinprick like haemorrhages (called petechiae) can be due to a local lesion, a generalised septicaemia or toxaemia caused by acute viral and bacterial infections.