Hello nhilcrest,
Good to have you here!
Be wary of unknown hermits! There are a few types commonly sold in the reef business, usually Blue Legs;
Scarlet Reef Hermits; Red Legs; and a couple more. Most of these, by themselves are pretty harmless, though their benefit in a coral reef tank is questionable. All are omnivorous and opportunistic feeders. In larger numbers, they may eat your snails and irritate your corals.
Many pet stores and some LFS will often carry other varieties of hermits that can grow large and even prey on your livestock.
These are the common hermits sold in the reef trade:
Scarlet Reef Hermit (Paguristes cadenati)
Blue Leg Hermit (Clibinarius tricolor), may be Phimochirus operculatus
Red Leg Hermit (Clibinarius digueti)
There are many closely related species of these crabs; I've had some Blue Legs that grew much larger than others, though they looked the same.
I personally avoid hermits after bad experiences with the Blue Legs killing my snails. I do keep a couple of Scarlet's, which are more benign, as they are neat to watch.
Please read this article:
http://www.animalnetwork.com/fish/li...=&RecordNo=166
If the crab doesn't look like one of the above, watch it carefully, especially if it grows larger.
HTH,
Dick)
