Got the info just in case anybody else is interested.
Common Hermit Crab
(Dardanus megistos)
Quick Stats Care Level: Easy Tank Conditions: 72-78?F; sg 1.023-1.025; pH 8.1-8.4; dKH 8-12 Color Form: Brown, Tan Temperament: Aggressive Reef Compatible: No Diet: Omnivore Origin: Eastern Atlantic Family: Diogenidae
The Common Hermit Crab has hairy red legs and unequal-sized claws (the left one is larger) which it will use to catch food. It lives inside empty gastropod shells and will attain a maximum size of approximately 8 inches.
The Common Hermit Crab is not safe for a reef aquarium because it will eat tube worms, mollusks, and fish. It will also eat algae. In a community tank, however, it will keep the sand sifted with its constant search for food. It is best to keep just one specimen per tank, since it is aggressive towards other Hermit Crabs. As the Hermit Crab grows, it will need larger shells to inhabit. It is most active at night. It is a very hardy animal, and an interesting addition to an aquarium.
If there is insufficient algae, the diet should be supplemented with dried seaweed, tablet foods, and earthworms.
Get these books and take them to the fish store with you:
Corals
a quick reference guide by Julian Sprung ISBN 1-883693-09-8
Marine Fishes A Pocket Exper Guide 500+ essential-to-know aquarium species ISBN 1-890087-38-6
Marine Invertebrates A Pocket Expert Guide 500+essential to know aquarium species ISBN1-890087-66-1
They have good unbiased info on what each animal needs to survive and how reef safe they are. Do not believe the little sales blurb next to the pictures. You will find many things that are mis represented or mislabeled both in stores and on line.
Thanks leslie , im glad I have internet because the person at the fish store told me those crabs where fine for my reef and I found out that they werent.It took me a while but I found them on liveaquaria.com. The fish store is not the regular I go to. I will look for those book I only have one "marine reef aquarium handbook" .
If you want a nice hermit crab ,look into getting eletric blue hermits they are about $5 each bigger then reg hermits and a really nice color ,they are also reef safe
Reef Lady, I had one of those crabs in my fish only and live rock tank for years. I liked the crab and tried to keep him when I changed to a reef tank.
All was good till one day I saw him sitting on top of a zoo colony ripping them to shreads with total glee. I found him a new home, he is now living with a nice family in new jersey.
Moral of this story beware the people at the LFS. Not all are bad, but as others have said many do not have a clue, or worse they just want to sell you something and don't care.