The head is pale with a blue chin and throat, the pectoral, pelvic and anal fins are yellow.

[4] The blue-headed wrasse occurs in sheltered to exposed rocky reefs, frequently being recorded where there is sea weeds as deep as 160 metres (520 ft).

The adults are normally to be found near the sea bed and prefer deeper waters than the juvenile fish.

The smaller fish are found in shallower water than the adults where they frequent beds of kelp and other seaweeds, as well as sea grass.

[5] The specific name tetricus means "grim", a reference to the somewhat forbidding appearance of large males.

The biology of this species makes it vulnerable to fishing pressure as the large, territorial males are most easily taken and this leads to a reduction in breeding success and lower recruitment into the population, There are concerns that the larger minimum size for catch in Tasmania does not provide adequate protection.