One might think initially that this false stonefish (Scorpaenopsis diabolus) is rather well camouflaged....
But then there is that big circular ring of pectoral fin rays it sits on. I mean that must be a bit of a give away right?
In response to that I would point out (on behalf of the aggrieved pseudo-stone) the prevalence in the region of these Fungia corals.
Not so easy now is it? In truth the fin rays and the eyes are the two things I usually notice immediately before my brain clicks into gear and I think "[ah scorpion/stone/devil[delete as appropriate]] fish" but I guess the point here is that eve if visible to prey that ring isn't such an unusual pattern on these reefs.