It's an easy boss for mages, just dps him.
If the raid dps is low and you will need 2 Pungent Blight cast to finish him, take the first series of Spores and Ice Block the 2d Pungent Blight (in order to maximize you casting time under 35% life of the boss)
If the raid dps is correct, just stay where you are don't take spores and Ice block on the Pungent Blight
Take care of the malleable goo, a good way to handle them is to play at the left side of the room behind you mates (you have a greater range then them) but take care to stay in range of the Wrath of Air Totem, and at range to have the concentration aura of the paladin.