Snapper-choking isopod

Cymothoa excisa

Family Cymothoidae - marine isopods

Body dorsoventrally compressed, 2-3 times longer than wide; color whitish; 7 pereonites (thoracic plates); 7 pereopods (legs), prehensile; terminal thoracic segment pointed on ends; abdomen narrower than upper body or tail; abdominal plates narrow; uropods (outer fans) on tail small, outer ones slightly longer than inner ones; telson (main tail fan) 2 times wider than long, broadly rounded, somewhat bilobed; eyes present but not prominent; antennae small.
Similar Species
Other marine parasites may be bilaterally compressed, may have a longer body, a twisted body, longer antennae, longer uropods, and/or a different number of legs.
Gulf and bays, parasitic
Maximum Size
26 mm (1 in)
Other Common Names
Previous Scientific Names
Parasite in the mouths of marine fishes.