Gnathia marleyi

Farquharson, Smit & Sikkel, 2012

Isopod

Range: Western Atlantic Ocean: Caribbean.

Note: This species feeds on fish blood and mucus.

Taxonomy:

Kingdom: Animalia

Phylum: Arthropoda

Class: Malacostraca

Order: Isopoda

Family: Gnathiidae

Genus: Gnathia

FYI: Isopods are a free-living mostly nocturnal crustacean found in both the freshwater and marine benthic environment and there are over 10,000 species and inhabit intertidal zones down to the deepest regions of the oceans.

Creature size varies from about 4 mm to some reaching over a foot (30 cm) in length. Yet most seen in the aquarium trade are usually less than a 0.5 inch (1 cm).

Most marine isopods are bottom slow crawling dwellers and feed upon organic debris, yet some have developed a parasitic lifestyle and can attach to a host, whether fish or other crustacean, suck its blood or simply consume its fins and flesh and either kill or greatly injury the host.

There's even one family where its species, Limnoria lignorum, can bore into marine timbers/pilings and causes severe damage.

Rarely seen in the aquarium, however, a few species are noted below so you can get an idea of what they look like - nothing that enhances home aquarium environments!

In fact, if a parasitic isopod is seen on a fish, it must be removed with forceps and the wound treated with antibiotics in a hospital tank until healed.

These are sometimes called 'Fish Lice.'