CICHIDS OF LAKE TANGANYIKA.
Order Perciformes
Family Cichlidae
Subfamily ( Pseudocrenilabrinae )
Genus Pseudosimochromis.
— Pseudosimochromis curvifrons [Poll, 1942]. Synonym: Simochromis curvifrons. Lake Tanganyika, northern part, rocky biotopes. 12-14 cm, in aquarium 7-10 cm. Distinctive features of this species include: • short head, cranial profile curves steeply towards the dorsal fin; • due to the steep profile and short head, it appears high-bodied; • straight-set mouth with a small mouth slit, positioned very low; • several rows of conical, bicuspid teeth are located on the jaws.
The caudal fin is slightly emarginate. The ends of the dorsal and anal fins, unlike most species, are not rounded. Members of this species have a pronounced sexual dichromatism: the gray-green male has one or two egg-spots on the anal fin, a brownish head, and no vertical banding on the body, while the female lacks egg-mimics on the anal fin and has 9 vertical coffee-colored stripes on the body. The female and juveniles are silver, with rounded dorsal and anal fins.
Color morphs: — P. curvifrons “South” – males have a silver body with a blue sheen; — P. curvifrons “North” – males have a silver body with a green sheen.
The aquarium should have areas of open water, a few pile-ups of rocks, and a bottom of fine or medium river sand. Plant thickets are usually not damaged. Males are territorial and very aggressive, it is advisable to keep only one male with a small group of females. Keeping several adult males in the same aquarium is unlikely to work out, and sometimes active males even chase females. Females can also chase each other. Diet: vegetable (70%) and animal (30%). Mature in 12-16 months. Males and females come together only during the breeding period. Only females incubate the eggs. dH 8-20°; pH 7.8-9.0; T 24-27°C.
Genus Plecodus.
Members of this species feed on the scales of other fish. The tooth structure is unusual. It has hook-shaped teeth curved inwards and adapted for scraping scales off other fish. There is a row of teeth on each jaw. Each tooth bends inward at a 90° angle as it emerges from the jaw. The tooth structure of these cichlids is adapted to their feeding method. Prey is usually attacked at speed in open areas. Plecodus swims up to the victim with its mouth open and, using its inward-curved teeth, grabs and tears off the scales. There is practically no practical experience in keeping this species.
— Plecodus multidentatus [Poll, 1952]. Congo. 12 cm. Sexual color dichromatism in these cichlids is not expressed. Distinctive features of this species include: • elongated body; massive upper back; • lyre-shaped caudal fin with an elongated filament in the lower part of the fin; • dorsal and anal fins have elongated outer rays. Each jaw has a single row of teeth that curve inward in a wide curve. The teeth are not only sharp but also very large. They feed on the scales of other fish. The attack on the prey occurs very rapidly and literally in a fraction of a second, with the attack carried out at full force and with an open mouth. The species is a mouthbrooder. Temperature 25-27°C; pH 7.8-8.5; dH 10-20°.
— Plecodus straeleni [Poll, 1948]. Lake Tanganyika. 15 cm. Distinctive features of this species include: • relative high-bodiedness compared to other scale-eaters, with the body giving the impression of being well-fed. A phenomenon is the coloration of Plecodus straeleni – with its striped blue-green coloration, the fish resemble the coloration of three well-known species: Cyphotilapia frontosa, Neolamprologus tretocephalus, and Neolamprologus sexfasciatus. Some geographic variants of Plecodus straeleni have six vertical stripes, while some have only five. The tail base and caudal fin are well developed, revealing the exterior of a good swimmer. This is an ideal option for a “scale-eater”, which of course is not a safe neighbor for potential victims.
Members of this species feed on the scales of other fish. Prey is usually attacked at speed in open areas and finds itself completely at the mercy of these energetic and strong fish. It can be said unequivocally that keeping them together will guarantee problems for species living in open water or on an open sandy bottom. Cichlids that spend most of their life in hiding places have a better chance of remaining unharmed. As a rule, they lead a solitary lifestyle, but form pairs before spawning.
Genus Perissodus.
The name of this genus arose in connection with the feeding method of its members. These fish attach themselves to their prey and tear off scales with their inward-curved teeth. Straight mouth with thick lips. Teeth are deeply set, wide at the base and forked at the ends.
— Perrissodus eccentricus [Liem & Stewart, 1976]. Lake Tanganyika. 16 cm. Distinctive features of this species include: an elongated and laterally compressed body with a large number of small scales; massive upper back; pointed head shape with relatively large eyes. Mouth – straight-set, curved with a deep oral cavity. Dorsal, anal, and pelvic fins with pointed ends, while the caudal fin is distinctly curved and very strong. The coloration of this species is very similar to that of Perissodus microlepis. Sexual dichromatism is absent.
The scale-eater does not change its habits even in home aquariums. It is naturally equipped with a jaw specially designed for this purpose. Unlike other scale-eating species that attack prey frontally at a right angle, Perissodus eccentricus can attack from a parallel position, fully utilizing the asymmetry of its curved mouth. Scales are grasped lightning-fast with hook-shaped teeth and torn from the victim’s body. They can only be kept in a very large aquarium with fish of the genus Altolamprologus.
Paracyprichromis brieni, Paracyprichromis nigripinnis.
Ophthalmotilapia heterodonta, Ophthalmotilapia ventralis. 
