[4] 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.

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.

[2] 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.

[4] All members of Syndontis have a structure called a premaxillary toothpad, which is located on the very front of the upper jaw of the mouth.

[4] On the lower jaw, or mandible, the teeth of Syndontis are attached to flexible, stalk-like structures and described as "s-shaped" or "hooked".

[3] Generally, females in the genus Synodontis tend to be slightly larger than males of the same age.

[1] The reproductive habits of most of the species of Synodontis are not known, beyond some instances of obtaining egg counts from gravid females.

[8] As a whole, species of Synodontis are omnivores, consuming insect larvae, algae, gastropods, bivalves, sponges, crustaceans, and the eggs of other fishes.