C. trewavasae belongs to the group of cichlids known as Utaka, which are true open water species. Utaka species, including C. trewavasae, feed on the zooplankton found in the open water column. Plankton is not always plentiful in the lake; there are specific locations, however, that can supply the huge shoals of Utaka a steady flow of fresh plankton. Utaka, of course, know right where to find these places, which are characterized by rocks or reefs on the sandy bottom. These rocks cause turbulence in the current just downstream. It is here that large clouds of plankton can be found along with the Utaka. Copadichromis species are characterized by highly protrusible mouths which shoot forward to form a tube, causing a negative pressure vacuum in its mouth, which then sucks the plankton in.

Males and females forage together throughout the year and only during a short breeding period do they migrate in masse inshore to spawn. Copadichromis trewavasae differs from the other Utaka species in its behavior inasmuch as it is a cave-crater bower builder. In other words, males will construct a large, volcano-like crater out of the sand, but the sandcastle crater is constructed against a rock with a cave burrowed out underneath it. It appears that the cave is the most important part of the sandcastle. This behavior is often times observed in the aquarium.

The adult, male specimen pictured below is representative of the population found at Msisi, Tanzania. It differs from the other varieties of C. trewavasae only in that has orange-red flecks in the dorsal and anal fins. Other varieties will either have a white or yellow trim on their anal fin and may differ in the extent of white on the body. Females are silver. This cichlid was formerly known as C. sp. "mloto likoma". Maximum total length is about 14 cm.