Jansen's wrasse (Thalassoma jansenii) is a species of wrasse native to the Indian Ocean and the western Pacific Ocean. It is a reef inhabitant, preferring rocky areas, and can be found at depths from 1 to 15 m (3.3 to 49.2 ft). This species can grow to 20 cm (7.9 in) in total length. Like many other coral reef wrasses, this species swims actively over the reef using solely their pectoral fins for thrust (known as labriform locomotion). It can also be found in the aquarium trade.