Thumbprint Emperor (species: Lethrinus harak) in Lizard Island Field Guide (Lizard Island Field Guide)
Lethrinus harak
Thumbprint Emperor

©Paul Asman: Lethrinus harak among mangrove roots in the Lizard Island lagoon.

©Andy Lewis: An adult Thumbprint Emperor

©Andy Lewis: An adult Thumbprint Emperor with a dark spot
Kingdom Animalia
Phylum Chordata
Class Actinopterygii
Order Perciformes
Family Lethrinidae
Genus Lethrinus
Species Lethrinus harak



Distinguishing features

A medium sized silvery fish with a large eye and a darker oval spot on the flank, which can vary in colour from very black to almost invisible. Dorsal, anal and pectoral fins often pinkish.


  • Up to 60 cm (Standard length)

Depth range

  • Depth range data is not yet available.



©Atlas of Living Australia: Australian distribution

Distribution and habitat preferences

Usually near areas of sand or rubble close to coral reef areas.

Can be found in most locations around the island.


This species is an active diurnal feeder, and hunts for crustaceans and other invertebrates over the reef flat. They tend to move in short bursts, then hover while they inspect the bottom, then move again, often stopping to take a bite from the substratum every now and then. The Emperors are protogynous hermaphrodites, starting life as females and then changing sex to male at a larger size. Maximum age for this species is reported to be 15 years.

Web resources


References that assist with identification

  • Randall, J.E., G.R. Allen and R.C. Steene (1990). Fishes of the Great Barrier Reef and Coral Sea University of Hawaii Press, Honolulu, Hawaii.

Other references

  • Arvedlund, M. and A. Takemura (2006). The importance of chemical environmental cues for juvenile Lethrinus nebulosus Forssk√•l (Lethrinidae, Teleostei) when settling into their first benthic habitat, Journal of Experimental Marine Biology and Ecology, 338: 112-122. LIRS catalog number 90061.
  • Bean, K., B.D.Mapstone, C.R. Davies, C.D. Murchie and A.J. Williams. (2003). Gonad development and evidence of protogyny in the red-throat emperor on the Great Barrier Reef, Journal of Fish Biology, 62: 299-310. LIRS catalog number 90062.
  • View all references