The Dusky Wrasse (Halichoeres Marginatus) also known as the Splendid Rainbow Wrasse, Rainbow Wrasse or Two Eyed Wrasse is not a commonly seen wrasse on the reefs of Tanzania and is a reclusive fish and quite hard to get close to. In its juvenile stage it is a brownish color with horizontal darker stripes across the body with a blue eye spot or dot halfway along its dorsal fin.
In its adult stage the fish earns its name as the Rainbow Wrasse and is occasionally seen slipping into holes in coral, being very reclusive at the sight of divers and seldom reemerging from its hole. It has a reddish nose with typical Halichoeres blue markings running back across its face, changing to yellow and blue going back over the body, darkening into blue and the dorsal ventral and anal fins are lined with a red and light blue stripe, truly a stunning fish when seen.
Its diet appears to be small mollusks and crustaceans along with tunicates and they can be seen picking their way across the reef.
It is found across the Indo Pacific region and is seen from one meter to thirty meters in depth generally around the reef and as a juvenile will bury its self in sand when frightened as with the other members of Halichoeres species.
It can be kept in a tank with other species of peaceful wrasses and its own species and will eat fire worms and snails which is good for clams although it may nip on feather duster worms. These Wrasses have been known to jump and care should be taken in this regard.