yellow sided conure bites my fingers

Iv had my yellow sided conure since he was 6 months old, he is now a year and a half. He likes me a lot, i always play with him whenever i get the chance, i even trust him enough to grow his wings out and let him fly around his room ( which is the our game room).

ever since i got him he has never bit me hard, or even tried to bite me only when he needed something, but a month ago he would aggressively but my fingers like hes on a mission to chop them off. I still love the litte bugger, and i still play with him everyday, and let him out. But this aggression problem is starting to really annoy me.

I also have a Cockatiel that i baught of a guy who didnt treat him right and hes starting to like me a lot aswell which is nice.
thanks for your help