False Upside-down Catfish

Like all members of the genus Synodontis, S. nigrita has a strong, bony head capsule that extends back as far as the first spine of the dorsal fin. The head contains a distinct narrow, bony, external protrusion called a humeral process. The shape and size of the humeral process helps to identify the species. In S. nigrita, the humeral process is as much longer than it is broad, with a ridge on the bottom edge, and with a pointed back end. The fish has three pairs of barbels. The maxillary barbels are on located on the upper jaw, and two pairs of mandibular barbels are on the lower jaw. The maxillary barbel is long and straight without any branches, with a broad membrane at the base. It extends to a length about 1 to 1+2⁄3 times the length of the head. The outer pair of mandibular barbels is about twice the length of the inner pair, and both pairs have short, simple branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. nigrita, the spine of the dorsal fin is straight or slightly curved, 3⁄4 to 1 times the length of the head, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays. The spine of the pectoral fin about the same size as the dorsal spine, and serrated on both sides. The adipose fin is 2+2⁄3 to 3 times as long as it is deep. …

In the wild, the species has been found throughout northern Africa. In central Africa, it has been recorded in the Ubangui River basin and the central Congo River basin. In eastern Africa, it is found in Lake Albert and possibly Lake Kyoga. In northern Africa, it is possibly present in Egypt. In northeast Africa, it occurs in the White Nile from Khartoum into the Jebel and Ghazal River systems, as well as the Baro River. In western Africa, the species is known from the Chad River basin, the Niger River basin, the Volta River, the Senegal River, the Gambia River, the Geba River, the Oueme River, and the Casamance River. The reproductive habits of most of the species of Synodontis are not known, beyond some instances of obtaining egg counts from gravid females. Spawning likely occurs during the flooding season between July and October, and pairs swim in unison during spawning. As a whole, species of Synodontis are omnivores, consuming insect larvae, algae, gastropods, bivalves, sponges, crustaceans, and the eggs of other fishes. The growth rate is rapid in the first year, then slows down as the fish age.