The Hermits don't mess with the Clam itself, but they will eat the algae that accumulates on its shell. Even when perched on rock or a pedestal of sorts, the Hermits can still reach it.
I've actually been surprised to see how well the Maxima defends itself in certain situations. For start, it can completely withdraw its mantle into its tightly closed shell, and that's pretty much game over until the curious intruder moves on. I also have a Starfish that I have to keep an eye on in regards to the Clam. I saw it climb on top of the Maxima one time, and the Maxima did its siphon water jet thing! It launched the Starfish no less than six inches into the water column and that was that. :lmao: