The Parasitic Isopod, Tongue-eating Louse, Fish Tongue Biter – Cymothoa exigua is a fascinating and rather gruesome parasite that invades the mouths of fish. This isopod, belonging to the genus Cymothoa, is notorious for its unique feeding behavior, which involves replacing the tongue of its host fish. This parasite is found in the Atlantic Ocean, specifically off the coast of California and the Gulf of Mexico, and has become a subject of curiosity and fascination for its unusual life cycle.
Description & Characteristics
The Cymothoa exigua is a small isopod, typically reaching a maximum size of about 1.5 centimeters. Its body is flattened dorsoventrally, allowing it to maneuver easily within the cramped confines of a fish’s mouth. The Cymothoa exigua possesses seven pairs of legs, with the first pair modified into strong, hooked appendages, which it uses to grasp onto the host fish’s tongue.
Habitat and Occurrence
The Cymothoa exigua is a marine parasite that primarily inhabits the coastal waters of the Atlantic Ocean, particularly off the coast of California and the Gulf of Mexico. It is commonly found in the neritic zone, which is the region of the ocean that extends from the shoreline out to the edge of the continental shelf. Within this zone, the Cymothoa exigua is often found clinging to fish, particularly those that reside in shallow, inshore waters.
Taxonomy
The species Cymothoa exigua belongs to the Class: Malacostraca, Order: Isopoda, and Family: Cymothoidae. The Malacostraca, the largest class within the subphylum Crustacea, includes a wide variety of crustaceans, many of which are familiar, such as crabs, lobsters, shrimp, and krill. Isopoda is an order of crustaceans that includes a diverse array of species, including pill bugs, woodlice, and marine isopods. The Cymothoidae, also known as fish lice, is a family of parasitic isopods, which are characterized by their adaptations for attaching to and feeding on fish.
Feeding
The Cymothoa exigua‘s unique feeding strategy involves replacing the tongue of its host fish. When a young Cymothoa exigua enters a fish’s mouth, it attaches itself to the tongue and begins feeding on the blood supply. As the Cymothoa exigua grows, it eventually cuts off the blood flow to the tongue, causing it to atrophy. Remarkably, the Cymothoa exigua then takes over the role of the tongue, becoming the fish’s new source of sensation for food. The Cymothoa exigua continues to feed on the blood and mucus of its host, essentially becoming a permanent resident within the fish’s mouth.
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