It doesn't follow it around. But if its chilling on the left side of the tank and the hermit is walking by it looks at it litr what the heck is that and then nips at it a couple times. It doesn't do this to my new fish though. They get along really well.Is it following the hermit around and bothering it, or is the hermit trying to head into the Gramma's territory? If it's the former, that is weird. If it's the latter, though, my Royal Gramma gets mad if anything in the tank (fish, snails, or crabs) get too close to "his" cave, and will both perform threat displays (at everything) and occasionally nip at the inverts until they go away.