Here’s a pixture of an Arrowcrab doing that same thing.
Had a little trouble w/ my strobe on this trip. I was firing but not at full power… so that’s why the sponge is a little bit too blue.
They are “cleaners” meaning that they remove parasites, dead skin etc from fish.
They advertise their willingness to perform this service by sitting near the openings of recesses or sponges (like this Purple Vase Sponge) and slowly waving their antennas to attract passing fish.
Definitely one of the many species of puffer.
But when I consult my fish ID book, I come away thinking that he has features of both the Balloonfish and the Porcupinefish.
I don’t know if this can happen… but perhaps he’s the love child of a cross-species relationship.
They are nocturnal hunters… so during the day you find them hanging out underneath the coral outcrops.
They have a tan to dark purple body with lots of gangly, spiny legs and antenna sticking out every which way.
They may be tasty to eat but they are, at least in my opinion, pretty ugly to look at.
