Boulenger first described Cunningtonia longiventralis in 1906. The genus name Cunningtonia is a name reference to Dr. W.A. Cunnington. The species name longiventralis is a reference to the elongated ventral fins. This species is a member of the ray-finned fishes or Actinopterygii.
A clear distinction between the other cichlids are the elongated pectoral fins of the Cunningtonia longiventralis, these resemble the pectoral fins of the Cunningtonia furcifer. Het body is torpedo-shaped. Depending on the location of the fish some colour variation can occur. The Kipili sub-species have a yellow coloured band in the dorsal fin and a yellow colouring in the tail but have a greyish colour. The Cape Nangu variaty is more bluish.
The Cunningtonia longiventralis lives in the Southern part of Lake Tanganyika. They occur from 5 to 20 metres.