Microspathodon chrysurus (Jewel damselfish) is a Damselfish from the Western Atlantic. It occasionally makes its way into the aquarium trade, where it is known as the Marine Jewelfish (not to be confused with the freshwater Cichlid, known as the Jewelfish) . It grows to a size of 21 cm in length. When juvenile it has brilliant (metallic) blue spots on a dark blue back ground. It is probably the most aggressive of all Damselfish, and should be kept with fish substantially larger and more robust than itself.