Bichir
Bichirs /ˈbɪʃɪərz/ and the reedfish comprise Polypteridae /pɒlɪpˈtɛrɪdiː/, a family of archaic ray-finned fishes and the only family in the order Polypteriformes /pəˈlɪptərɪfɔːrmiːz/.[2]
All the species occur in freshwater habitats in tropical Africa and the Nile River system, mainly swampy, shallow floodplains and estuaries.
Cladistia, polypterids and their fossil relatives, are considered the sister group to all other extant ray-finned fishes (Actinopteri).[3][4]
Polypterids are elongated fish with a unique series of dorsal finlets which vary in number from seven to 18, instead of a single dorsal fin. Each of the dorsal finlets has bifid (double-edged) tips, and are the only fins with spines; the rest of the fins are composed of soft rays. The body is covered in thick, bonelike, and rhombic (ganoid) scales. Their jaw structure more closely resembles that of the tetrapods than that of the teleost fishes. Bichirs have a number of other primitive characteristics, including fleshy pectoral fins superficially similar to those of lobe-finned fishes.[1] They also have a pair of slit-like spiracles on the top of their heads that are used to breathe air,[5] two gular plates, and paired ventral lungs (the left lung shorter than the right).[6] Four pairs of gill arches are present.[7]
Polypterids have a maximum body length ranging from 25 cm (9.8 in) to over 100 cm (39 in) depending on specific species and morphology.[8]
Polypterids are nocturnal and feed on small vertebrates, crustaceans, and insects.[1] Their common aquarium diet includes bloodworms (Chironomidae larvae). Polypterids are known to have extraordinary olfactory ability. Polypterid reproduction consists of the female laying anywhere from 100 to 300 eggs over the span of a few days, and subsequent fertilization by the male.[9]
