Cichlid

Diagnosis: A heavily-built large tilapia species with a wide rounded head and short jaws; individuals vary a lot in dentition, with some having very wide bands of jaw teeth (Ref. 118638). Head length 30.8-36.0% of standard length; lower pharyngeal with large toothed area with straight or slightly convex sides; median length of pharyngeal bone 1.14-1.32 times its width and 38.2-42.2% of head length; blade 1.0-1.7 times median length of toothed area; length of lower jaw 28.4-34.5% of head length; teeth of jaws in 4-6 rows (Ref. 2). Females and juveniles with greyish-brown bodies and 4-5 vertical bars (Ref. 118638). Males are black with a white margin to the dorsal and tailfins; the genital tassel can be long and branched and pinkish to bright yellow (Ref. 2, 118638). It is one of the 'chambo' group Oreochromis from the Lake Malawi catchment; females and non-territorial males cannot be reliably distinguished from those of Oreochromis squamipinnis; females and non-territorial males from Lake Ikapu are a bright golden colour (Ref. 118638).Description: Upper profile of snout before eye usually convex (Ref. 55427). Jaws small (Ref. 6150). Tooth band wide (Ref. 4967). Lower pharyngeal bone heavily developed; size of head and jaws, depth of body and number of tooth rows population dependent (Ref. 55079). Sides of triangular toothed area of lower pharyngeal bone not concave (Ref. 55427). Caudal fin scaly (Ref. 2, 55427) and emarginate (Ref. 2). In adults both upper and lower lobes of caudal fin rounded; caudal peduncle as long as or longer than deep; genital papilla prominent and bifid in breeding fishes (Ref. 2). Males develop a breeding dress (Ref. 5595) and a genital tassel (Ref. 5595, 44514), each branch bearing tubercles and filaments (Ref. 2).Colouration: Non-breeding fish: silver-grey, darker on the dorsum, with black vertical bars of uneven length from the dorsum to mid-flanks (Ref. 2). Ripe females: very dark, almost black (Ref. 55079). At some times of the year (Ref. 55079) females, juveniles and non-breeding fish develop a yellowish-brown body with yellow margin to the dorsal fin (Ref. 6150, 55079). Courting male: black (Ref. 2781, 4967, 6150, 55079), often with iridescent patches on the head or body (Ref. 55079). Flank scales often with coppery metallic spot (Ref. 55079). Broad white margins to dorsal (Ref. 2, 55427) and caudal fin and sometimes also to the anal fin (Ref. 2). Black color lost in a few seconds when alarmed, turning a pale grey, often with iridescent greenish or coppery areas on the flanks or head (Ref. 40193).

A maternal mouthbrooder; males defend territories from shallow water down to at least 28m; males dig pits, which are sometimes huge craters with a small raised platform of fine sand (Ref. 118638). Breeding period extends over several months as noted in Lake Malombe, at present one of the main breeding areas for this species (Ref. 6150). Males build nests on a variety of substrata and at depths of 0.5m to at least 28m; nests generally 0.3-1.9m diameter, with dimensions correlated to male size (Ref. 55079). Nest with a characteristic spawning cone in its center (Ref. 5595). Courtship appears to occur mainly in the early morning (Ref. 40193, 55079), and consist of leading, followed by tilting and head-down quivering if the female follows the male to the nest (Ref. 40193). A female with 324 young of 15mm long in the mouth has been caught (Ref. 2781). Females keep guarding their fry until they are about 24 mm (Ref. 2781, 6150).

Dorsal spines (total): 15 - 17; Dorsal soft rays (total): 10 - 12; Analspines: 3; Analsoft rays: 8 - 10; Vertebrae: 30 - 32

It is found in all kinds of habitats; it has been observed in shallow vegetated bays, in intermediate habitats, over sand, and in purely rocky biotopes (Ref. 5595). At most locations it is found at shallow levels, rarely deeper than 10 metres (Ref. 5595), but it can be present from the surface waters to depths of 40-50m (Ref. 118638). It feeds on phytoplankton and on diatom sediment on the sand; the so-called 'multitooth' morph at Cape Maclear grazes from rocks and might harvest the loose aufwuchs (Ref. 5595).

It is found in all kinds of habitats; it has been observed in shallow vegetated bays, in intermediate habitats, over sand, and in purely rocky biotopes (Ref. 5595). At most locations it is found at shallow levels, rarely deeper than 10 metres (Ref. 5595), but it can be present from the surface waters to depths of 40-50m (Ref. 118638). It feeds on phytoplankton and on diatom sediment on the sand; the so-called 'multitooth' morph at Cape Maclear grazes from rocks and might harvest the loose aufwuchs (Ref. 5595). A maternal mouthbrooder; males defend territories from shallow water down to at least 28m; males dig pits, which are sometimes huge craters with a small raised platform of fine sand (Ref. 118638). It is an important component of the fisheries catch in Lake Malawi (Ref. 118638). The IUCN conservation status is rated as endangered, based on declining fishery catches due to overfishing (Ref. 118638).

fisheries: commercial

Oreochromis karongae is a critically endangered species of cichlid that is endemic to Lake Malawi, Lake Malombe, and upper and middle Shire River in Malawi, Mozambique, and Tanzania. This species is important to local commercial fisheries, but has declined drastically due to overfishing.

It can reach a total length of 42 centimetres (17 in). Breeding males are black with white edges to the fins and are extremely similar to breeding male O. lidole, while females are more yellowish-brown than females of O. lidole and O. squamipinnis.

It is part of the subgenus Nyasalapia, which are known as chambo. A taxonomic review recommended that O. saka should be considered a synonym of O. karongae (the two only differ by pharyngeal bones and teeth), but at present both are considered valid by FishBase.

The breeding males of chambo have long genital tassels that somewhat resemble fish eggs. During breeding, the female attempts to pick them up with her mouth and this helps the male in fertilizing the female's eggs, already in her mouth. O. karongae mainly feeds on phytoplankton, including diatoms.

The lepidophagous cichlid Corematodus shiranus is an aggressive mimic of chambo in both color pattern and swimming mode. It is, therefore, able to approach unsuspecting schools of chambo and rapidly take a mouthful of scales or fin.