The Senegal bichir (Polypterus senegalus) also known as the gray bichir and Cuvier's bichir, is sometimes called the "dinosaur eel" (a misnomer, as the creature is not an eel nor a dinosaur) and also known as "dragon fish" at many local pet chains. It is a prototypical species of fish in 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 other bichirs, reaching about 35.5 cm (14 in).
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.
Three subspecies of P. senegalus are recognized: P. s. senegalus, P. s. meridionalis, and a further unnamed subspecies.
- P. s. senegalus grows to about 80 cm (20 in) in the wild, and 48 cm (12 in) in captivity. It is a uniform brownish-grey to olive color on the dorsal surface, and the ventral surface is whitish. No banding occurs on adults, but very young juveniles show three horizontal bands. The upper jaw is slightly longer than lower jaw. It has eight to 11 dorsal finlets.
- P. s. meridionalis grows to about 110 cm (28 in) in the wild, and 56 cm (14 in) in captivity. It is a uniform olive-grey color on the dorsal surface. The upper and lower jaws are about the same length. It has 9 or 10 dorsal spines. P. s. meridionalis may be a regional variant of P. s. senegalus.
Bichirs are predatory fish; in captivity they will take any live or dead animal that can be swallowed or broken apart and then swallowed. Only its lack of speed prevents a bichir from emptying an aquarium of smaller fish; the pectoral fins only allow for slow cruising, and while it can achieve amazing bursts of speed, it cannot 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. It will also bite fins of other fishes if it can.
Provided the skin remains moist, P. senegalus can remain out of the water indefinitely – it can even be raised on land, where it uses its large pectoral fins to walk.
- Bruet BJ, Song J, Boyce MC, Ortiz C (September 2008). "Materials design principles of ancient fish armour". Nature Materials 7 (9): 748–56. doi:10.1038/nmat2231. PMID 18660814. Lay summary – New Scientist (January 25, 2013).
- Standen EM, Du TY, Larsson HC (August 2014). "Developmental plasticity and the origin of tetrapods". Nature. doi:10.1038/nature13708. PMID 25162530.
- Froese, Rainer and Pauly, Daniel, eds. (2005). "Polypterus senegalus" in FishBase. May 2005 version.
- "Polypterus senegalus". Integrated Taxonomic Information System. Retrieved 4 May 2005.
- Senegal Bichir – Polypterus senegalus, BioFresh Cabinet of Freshwater Curiosities.
- Fish scales may point to armor of the future
- Dinosaur eel inspires bulletproof armor
- Care information for Senegal Bichir at The Aquarium Wiki