Pentastomid Infections in Fish1

The pentastomes are a group of worm-like parasites that infect many different species of fish. Infections have been found in several families of fish including the Cichlidae (tilapia), Cyprinidae (danios), Cyprinodontidae (flagfish), and Poecilidae (mosquitofish, swordtails, mollies, platies). Although pentastomes are small, they can be seen without the use of a microscope. However, a microscope will help to differentiate them from other similar parasites. Pentastomes in fish resemble very small white, segmented grubs or worms (Figure 1). However, they are more closely related to fish lice such as Argulus than to true worms. They are believed to be close relatives of members of the group of organisms known as Crustacea, which include crabs, lobsters and shrimp, as well as the parasitic fish louse. Adult pentastomes, which are found in reptiles, look differen