Re: discipline, you might impose some restriction from a favored activity for a couple of days, and also insist that he do something nice for the child he bit. Obviously you can't guarantee there won't be another episode, but your clear rejection of this behavior will help. There's no need to overreact to a single episode, so I'd be careful not to act in a disproportionate way. There's no need to seek any specialized therapy for him, but it certainly makes sense to speak with him about different ways he can express his anger or dissatisfaction, ways that will respect other people's safety.