Stenorhynchus seticornis is the arrow crab. Its body is triangular, with long and thin legs. They are up to 10 cm (3.9 in) across, and the animal's carapace may be up to 6 cm (2.4 in) long. They have a lot of different colors on their bodies.

Stenorhynchus seticornis, the yellowline arrow crab or simply arrow crab, is a species of marine crab. Taxonomy Stenorhynchus seticornis was first described by Johann Friedrich Wilhelm Herbst in 1788, under the name Cancer seticornis.

The most common Arrow Crab (Stenorhynchus seticornis) comes from the Caribbean, but other species are imported from the Indo-Pacific region, eastern Africa, and California. They normally inhabit portions of the reef usually associated with a small cave or crevice. It is a hardy, long-lived invertebrate, that can be housed in the reef aquarium.