[3] Like all members of the genus Synodontis, S. petricola has a strong, bony head capsule that extends back as far as the first spine of the dorsal fin.

[4] The head contains a distinct narrow, bony external protrusion called a humeral process.

In S. petricola, the humeral process is triangular, rough, and is covered in many small, thin papillae.

The maxillary barbel has a narrow membrane attached near the base and is straight without any branches.

The exact purpose of the skin folds is not known, but is a characteristic of the species of Syndontis that are endemic to Lake Tanganyika.

[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".

[4] The back of the fish is yellowish to copper-brown and is covered with large, irregularly-shaped black spots.

[2][4] In general in Synodontis species, females tend to be slightly larger than males of the same age.

[7] It inhabits rocky shorelines in the littoral zone, to a maximum depth of 30 metres (98 ft).

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

[8] Juveniles appear to be carnivorous, feeding on water mites, seed shrimp, and insect larvae.

It lives among rock piles frequented by various species of Mbuna: small African cichlids.