Fish Identification Photos: Long Claw River Prawn, Macrobrachium tenellum: The Long Claw River Prawn is light brown with an iridescent blue-green tinge. Interestingly the Long Claw River Prawn carrieds it claws differently; the smaller left claw is always open, while the larger right claw is held closed. The longer claw is approximately 1.5 times longer than the length of the body. The body is approximately 3 inches in length and varies in weight from 4 grams to 9 grams.

In Mexico, the Long Claw River Prawn is found in the fresh water rivers that empty into the Sea of Cortez south of Loreto and along the coast of the mainland south to Guatemala. It is collected and sold commercially in the State of Guerrero, just north of Acapulco.

The Long Claw River Prawn is a decapod crustacean belonging to the Palaemonidae Family, characterized by members having a prominent rostrum (beak) and an abdomen bearing a tail fan.

They have eyes that are on stalks, and the carapace (shell) completely covers the dorsal and lateral thorax.

They have long thin legs with the second pair longer than the first and they have moderately large chelae (claws).

They are found only in fresh water. Prawns can be distinguished from Crayfish (Parasticidae Family) and Shrimp (Atyidae Family) by the relative proportions of the first and second legs, by the relatively slender chelae on those legs, and by the third pair of legs that lack chelae.

Long Claw River Prawn, Macrobrachium tenellum: Caught in August 2005, at the mouth of the river, San Jose Del Cabo, Baja California Sur, Mexico, by locals using a cast net. Size approximately 3 inches. Used as a superior live bait by surf fishermen. Description and photo courtesy John Snow.