These beautiful little crabs have a variety of colors, from red and orange to a blue purple. They are very hardy and live for a long time. They are rarely available to the hobbyist and add lots of color to any aquarium. They are docile crabs that like to cruise the aquarium. Crabs belong to the Class Crustacea and Order Decapoda, which is characterized by two pair of antennae, three body parts, and five pairs of legs. The head of a Crab is connected to the thorax and covered by a shell called carapace. They have a smaller abdomen and tail compared to Shrimp and they keep this tucked beneath the carapace. The first pair of their legs are usually developed claws which they use to gather food, use as protection, and to move objects. In order for Crabs to grow they need to shed their exoskeleton, a process called "molting", which allows them to remove their restricting shell and begin a new one. Often times in the home aquarium Crabs will leave this translucent shell in full view so it can serve as a distraction while the Crab finds a hiding place and allows its new shell to harden. This crab can grow to 4 inches.