~140 species (see list) Argulus is a genus of fish lice in the family Argulidae.

[1][2][3][4] They occur in marine, brackish, and freshwater environments.

[1] They sit tightly against the host body,[5] this minimises risk of detachment.

As juveniles, these species feed on mucous and skin cells of their host.

[6] At least some species can have severe impacts on their host populations.