The common seahorse is a relatively large species, which is not common as the English name suggests, but is classified as Vulnerable by the IUCN Red List of Threatened Species (2). Like all seahorses, the head is held at right angles to the body, the eyes can move independently of each other, and the tail is prehensile. Instead of having scales, as in most other fish, seahorses have a layer of skin stretched over bony plates that are visible as rings passing around the trunk (4). Swimming is powered by the rapidly oscillating dorsal fin, and they steer using the fins on either side of the body (the pectoral fins) (5). The common seahorse has a deep head and body and a thick, robust snout. Individuals are often completely black or they may be yellowish or cream with large dark spots. In common with other seahorses, this species is a master of camouflage, and may occasionally be sandy in colour in order to blend in with the background (2).