EXCLUSIVE

The hot tub fun is over for UCLA quarterback Josh Rosen ... school officials tell TMZ Sports it's been REMOVED from his dorm room after photos of the party pool went viral.

We spoke with UCLA Associate Media Director, Ricardo Vazquez, who tells us, "We have been told that the hot tub has been removed from his room. It’s gone."

Vazquez says the tub violated the UCLA residential housing policy which states, "Furnishings which are not officially designated as part of a residential room’s accessories may not be moved into any resident’s room at any time."

Sucks for Rosen ... dude seemed to be putting the tub to good use.