Wednesday, September 29, 2010

September 29, 2010 : Sengeal Birchir

Senegal Bichir

The Senegal Bichir, Polypterus senegalus, also known as the Gray Bichir and Cuvier's Bichir, is sometimes called the "dinosaur eel" at many local pet chains - a misnomer, as the creature is not an eel. It is a fish, a prototypical species of the Polypterus genus, meaning most of its features are held across the genus.

The body is long and about as deep as it is wide. A serrated dorsal fin runs along most of the body until it meets the caudal fin. The pectoral fins attach just behind and below the gill openings and are the primary means of locomotion, providing a slow, graceful appearance. P. senegalus is smaller than its brethren, reaching about 35.5 cm (14").

The head is small and lizard-like with a gaping mouth and small eyes on either side. Since its eyesight is poor the bichir primarily hunts by smell. External nostrils protrude from the nose of the fish to enable this.

The fish has a pair of primitive lungs instead of a swim bladder, allowing it to periodically gulp air from the surface of the water. In the aquarium bichirs can be observed dashing to the surface for this purpose. Provided the skin remains moist, the creature can remain out of the water for near indefinite periods of time.

This bichir's skin serves as a particularly effective armor.

Bichirs are predatory fish and in captivity will take any live or dead animal that can be swallowed or broken apart and then swallowed. The only thing preventing a bichir from emptying an aquarium of smaller fish is its speed; the pectoral fins only allow for slow cruising, and while it can achieve amazing bursts of speed, it can't catch fish of average speed. Given enough time, any fish that can fit in the bichir's mouth will be eaten; this fish should not be kept with any other fish smaller than three inches.

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