Pelvicachromis pulcher is a freshwater fish of the cichlid family, endemic to Nigeria and Cameroon. It is popular amongst aquarium hobbyists, and is most commonly sold under the name kribensis, although it has other common names, including various derivatives and color morphs of the kribensis: krib, common krib, red krib, super-red krib and rainbow krib, along with rainbow cichlid and purple cichlid.
In the wild, male P. pulcher grow to a maximum length of approximately 12.5 centimetres (4.9 in) and a maximum weight of 9.5 grams (0.34 oz). Females are smaller and deeper bodied, growing to a maximum length of 8.1 cm (3.2 in) and a maximum weight of 9.4 g (0.33 oz). Both sexes have a dark longitudinal stripe that runs from the caudal fin to the mouth and pink to red abdomens, the intensity of which changes during courtship and breeding. The dorsal and caudal fins also may bear gold-ringed eye spots or ocelli. Males show colour polymorphisms in some populations collected at single localities. Juveniles are monomorphic until approximately six months of age.
Pelvicachromis pulcher is native to southern Nigeria and to coastal areas of Cameroon, where it occurs in warm (24–26 °C or 75–79 °F), acidic to neutral (pH 5.6–6.2), soft water (12–22 mg L−1 CaCO3). Populations of P. pulcher also occur outside its natural range in Hawaii, USA as a by-product of the ornamental fish trade.
The species inhabits both slow and fast-moving water, though it is only found where patches of dense vegetation are available. Other fish that share the habitat of P. pulcher include other Pelvicachromis species (Pelvicachromis taeniatus), other cichlid species (Chromidotilapia guntheri, Hemichromis cristatus and H. fasciatus, Tilapia mariae and T. zilli) along with Brycinus longipinnis and Aphyosemion species. The species is prey for a number of rheophilic predators including Hepsetus odoe, Hydrocynus forskahlii, and Lates niloticus (Nile perch). In the natural habitat, P. pulcher have been observed excavating, defending, and sheltering in caves dug underneath plants, and these holes are also used for breeding. Not all P. pulcher, however, claim territories and many live in large, non-reproductive aggregates.
Despite the suggestion in some aquarium literature that the species feeds on worms, crustaceans, and insects, analysis of the stomach contents of wild P. pulcher suggests this is incorrect. A study by Nwadiaro (1985) of 161 individuals showed that the main food items were diatoms, green algae, pieces of higher plants, along with blue-green algae. Invertebrates, though consumed, were found to be relatively uncommon food items for wild fish.
Pelvicachromis pulcher is a popular cichlid for the aquarium.
