Fishes - Australian Museum Fish Site

Frequently Asked Questions

What is a Leatherjacket Louse?

Leatherjacket Louse - upper surface
Upper surface of the Leatherjacket Louse. View larger image.
Leatherjacket Louse - lower surface
Lower surface of the Leatherjacket Louse. View larger image.
Leatherjacket Louse and fish
A Yellow-finned Leatherjacket and a parasitic Leatherjacket Louse. The louse was removed from the whitish slit in the leatherjacket's belly. View larger image.

The images show a female Leatherjacket Louse Ourozeuktes owenii that was removed from a Yellow-finned Leatherjacket (view fact sheet).

The fish was collected by Australian Museum staff diving at a depth of 10m, Balls Head Bay, Sydney Harbour, May 2001 (AMS I.40836-008).

The Leatherjacket Louse is a species of parasitic cymothoid isopod that occurs in Australia's temperate marine waters.

It burrows its way through the body wall of the fish until it enters the body cavity. There it feeds on the host's tissues often in the region of the liver. View an image of a Leatherjacket Louse projecting through the body wall of a leatherjacket.

The Leatherjacket Louse is never totally concealed inside the fish. The posterior part of the louse always projects through a slit in the body wall.

The adult female Leatherjacket Louse like the individual in the images grows very large and never leaves the host.

Further reading

  1. Hale, H. M. 1929. The Crustaceans of South Australia. Harrison Weir - Government Printer, Adelaide. Pp. 380.
australian museum onlineabout the museumresearch and collectionsfeaturesexplore