Cymothoid Isopod
Anilocra spp and Renocila spp
To 2.5cm. 

Tan to dark brown bodies of
overlapping scales. Attached to species specific regions on the heads of several fish species.

Cymothoids exhibit various adaptations to their carnivorous and parasitic lifestyles. As juveniles they are not specific in their requirements and attach themselves temporarily to the skin of any fish. They produce anticoagulants and suck the fish's blood. They detach from their first host and later find another host. When they have found the correct species of fish for their adult development, they attach more permanently.

As adults, most species require a particular host species and are also site-specific. Locations for attachment chosen by different species of parasite include the skin, the fins, the gills and the mouth, and some species bore into muscle. These parasites can cause serious damage to their hosts, ranging from slow growth rate, through tissue damage and anaemia, to death.

Life Cycle
Protandrous hermaphrodites. Each juvenile develops first into a male, but if there are no females nearby, the male will later become a female and attach permanently to the host. This female is able to secretes pheromones which prevent male cymothoids in the vicinity from becoming female
    Ecological Descriptors
Habitat Size (cm) Diet Behaviour Sex 
Ectoparasite 2.5 Blood I/ Pr PGH
Cymothoid Isopod on French Grunt
Cymothoid Isopod