The Saltwater Arrow Crab is a hardy and long living crab that likes to be on rocks scavenging for food. Supplementing food for them is a good idea. Very enjoyable to watch as they move in odd ways. The Arrow Crab is a fantastic scavengers which are highly sought after for their diet of Bristle Worms and Flat Worms. It is highly recommended that only one be kept per tank and they should only be kept in larger tanks. It is a very unique crab and extremely helpful in the reef by eating bristle worms. It has very long legs that can be up to three times it's body length.