The dwarf cichlids of the genus Pelvicachromis are commonly referred to as Kribs, particularly Pelvicachromis pulcher. Older books sometimes place these cichlids in a different genus, Pelmatochromis, a genus that has long since been redefined. When it was initially imported, Pelvicachromis pulcher was mistakenly identified as Pelmatochromis kribensis, a totally different fish, but it is from this misidentification that their common name "krib" or "kribensis" is derived. The various species of Pelvicachromis differ only slightly in needs, and all have proven to be excellent aquarium fish. Indeed, for many aquarists, Kribs are ideal subjects for learning about breeding egg-laying fish and managing cichlid behaviour, being both easy to breed and easy to accommodate.
Pelvicachromis are confined to low-lying streams and rivers along the coastal regions of western and equatorial Africa. Kribs live in shady areas around sunken wood and tree roots where the water current is diminished, but they are not commonly found in standing water. Kribs dig caves underneath logs and stones where laying their eggs on the solid surface above them.
Kribs are adaptable and can be maintained in anything from relatively soft and acidic freshwater through to slightly brackish water. For breeding purposes though, pH becomes more critical because sex determination appears to be controlled by pH. In the case of common Kribs, the optimal pH is 7.0, at which broods will comprise equal numbers of males and females. As the pH becomes more acidic, the proportion of females increases, whereas making the pH more alkaline increases the proportion of males in the brood. The optimal pH for Pelvicachromis subocellatus and Pelvicachromis taeniatus is around 6.5, and for the giant krib Pelvicachromis sp. aff. pulcher the optimal pH is 6.0. Water temperature should be around 75F for maintenance purposes and 77-80F for breeding.
These are bottom dwelling fish, and caves, large plants, and other sources of shade are much appreciated. They enjoy rooting about in sand, but they can also be kept in tanks with gravel substrates as well. They do not uproot plants. As with almost all cichlids, water quality needs to be good. Otherwise, they are not fussy and will work in any tank from 10 gallons upwards.
Kribs are omnivores and will eat a variety of things. Flake, bloodworms, brine shrimp, daphnia, and Tubifex are all enjoyed. Some algae seems to be important, and wild fish are not to be at least partially herbivorous, and cooked spinach or a vegetarian flake food will make a good addition to the diet. If not provided with alternative green foods, Kribs will nibble at soft plants in the aquarium, though rarely to the point of causing serious damage.
Nothing serious here -- these fish are remarkably durable and show little sensitivity to the bacterial and microbial things like Hexamita (hole-in-the-head disease) that plague other dwarf cichlids. Provided Kribs are given good water and proper foods, they can be expected to thrive in any home aquarium. Quarantining is always a good idea though, especially with newly imported wild-caught fish.
Unlike many other dwarf cichlids (such as Apistogramma spp.) form stable pairs. In fact, Kribs seem to "mate for life" and stay loyal to one another even in the presence of alternative potential mates. Another distinctive feature of their behaviour is that the females are quite clearly in charge: females initiate spawning, guard the eggs, and for most of the time guard the fry as well. Males are largely relegated to keeping the territory safe and looking after the fry when the female is feeding. Characteristic of the genus are the shiny pink to purple bellies of the females. During spawning especially, the females become intensely coloured, far outshining the males in attractiveness.
Although often sold as community fish, this does need to be understood in context. Compared with most other cichlids, Kribs hold small territories (about 12" by 12") and defend them only while spawning, and even then only against bottom-dwelling fish that they few as potential threats. In other words, Kribs work very well in community tanks alongside midwater fish such as danios, small barbs, and tetras. Fish that stay close to the surface, such as hatchetfish and guppies, can also be expected to do well. In fact, the addition of harmless "dither fish" at the top of the tank seems to help give Kribs a sense of security, encouraging them to settle in and spawn more readily. However, bottom-dwellers such as Corydoras will be pecked mercilessly, and Kribs have been known to seriously damage small catfish. Similarly, Kribs are a bit too large to be entirely safe with Apistogramma or Microgeophagus spp. unless the tank is so large that all the cichlids can maintain their own territories without coming into conflict.
Breeding Kribs is not difficult. Any aquarist who can rear livebearer fry can rear Kribs. A 10-gallon tank is the minimum for a single breeding pair. The key addition to a breeding tank is a cave of some type, such as small flowerpot or half a coconut shell. Add some floating plants for shade. Spawning takes place inside caves, usually on the ceiling. The female guards the eggs alone. Often, it is the sudden disappearance of the female for a few days that indicates that spawning has taken place. A clutch of eggs can be as small as 20 or as many as 300. The eggs hatch after about two days, and the fry become free swimming about five days later. The female will now shepherd the fry around the tank to feed. Gradually, the male is allowed back into the family, and after the fry have been free swimming for a few days the male and female will alternate parental duties, one fish guarding the fry and the other fish going off to feed. Nonetheless, the female is clearly the dominant partner in the relationship and will look after the fry most of the time.
All species of Pelvicachromis are excellent parents and will take care of issues like removing sterile eggs and eggs that have become infected with fungus. Once the fry become mobile, they will eat a variety of foods, including algae, powdered flake food (such as Hikari First Bites), and liquid fry food (such as Liquifry for Egg Layers). The parents are very helpful, leading the fry around the tank to potential patches of food and if necessary, chewing up things like large flakes and spitting out smaller particles that the fry can manage. Newly hatched brine shrimp and, after about three weeks, small daphnia and bloodworms, will of course be relished, but they are not essential, and it is perfectly possible to rear a batch of baby Kribs on nothing more than liquid and powdered flake foods.
The fry grow rapidly, and the parents will start to lose interest in them after about a month or so, and may start showing signs of wanting to spawn again. They aren't hostile to their current brood though, and can be left together for a few more weeks without problems, though it may be easier to remove the fry to another tank for growing on, and letting the parents concentrate on another brood. After three months the fry can be sexed, and they are sexually mature within about eight months.
The only issue with breeding Kribs that needs thinking about is the pH problem mentioned above. For each species there is an ideal pH at which equal numbers of male and female fry are produced. If the pH is too high, more males and produced, if the pH is too low, more females are produced. It is entirely possible to end up with batches containing just one sex, and such batches are difficult to pass on to aquarium shops.
comment on Neale's Krib article
Species and varieties
One confusing aspect to identifying Kribs is that many species are subdivided into regional varieties that in some cases look very different to the standard form seen in fish books. This is especially true for Pelvicachromis subocellatus and Pelvicachromis taeniatus. These varieties generally don't matter much from a husbandry point of view -- all varieties within a single species can be kept in much the same way -- but it is important not to keep them in the same tank or crossbreeding will occur.
Pelvicachromis pulcher is the common krib widely sold in aquarium shops. Common Kribs are found in coastal rivers and streams in Nigeria, particularly the Niger Delta. Although sometimes found in slightly brackish water, they are primarily freshwater fish. For breeding purposes, slightly soft to moderately hard water with a neutral pH is preferred. Virtually all stock offered for sale is captive bred, often by hobbyists who regularly bring in excess fry. Adult males are about 3.5-4" in length and rather cylindrical in shape with long, tapering dorsal, anal, and caudal fins. Adult females are shorter and more compact and their fins are less elaborate. Colouration is very variable, but typically female Kribs sport a rose-coloured patch across the belly and a few gold-bordered eyespots at the back of the dorsal fin. Males have a less brightly coloured patch on the belly and typically lack the eyespots on the dorsal fin but may have some on the caudal fin instead. Running along the top half of the body are two longitudinal chocolate brown bands on either side of a golden band, though the colours of these tend to be rather weak on males and most vivid on females in breeding condition. Unfortunately, the mass production of Kribs on fish farms hasn't been very selective, and many of the fish offered for sale are poorly marked compared with some of the wild-caught fish. Potential breeders may want to shop around to find the best males and females they can rather than simply buying the first two Kribs they see.
Pelvicachromis subocellatus is much less frequently seen than the common krib. It is found along the equatorial African coastline from Gabon to the Republic of Congo occurring in both fresh and slightly brackish waters. For breeding purposes, the water should be soft and slightly acidic, around pH 6.0 to 6.5. Males are relatively drab animals with greenish-yellow bodies, golden heads, and prominent eyespots on the upper half of the caudal fin. Females in breeding condition on the other hand are spectacular: the purple patch on the belly becomes very vivid and is bounded by thick charcoal grey bands in front and behind. Pelvicachromis subocellatus are more deeply bodied than common Kribs. Male Pelvicachromis subocellatus have rounded caudal fins rather than the tapering caudal fins seen on common Kribs.
Pelvicachromis taeniatus is rather more commonly sold than Pelvicachromis subocellatus. It is smaller than the common krib (males get to around 3"). These fish seem to be just as hardy and adaptable as the other Kribs despite their smaller size, though a slightly acidic (6.5) or neutral pH seems to be the ideal for breeding. Although superficially similar to common Kribs at first glance, both sexes can be distinguished from common Kribs by their bright yellow upper lips and rounded caudal fins. Most varieties also have quite prominent silvery-blue eyespots on the gill covers and males commonly have large, dark brown eyespots fringed with yellow on the caudal fin. There are at least a dozen recognized varieties of Pelvicachromis taeniatus, of which some of the more common are listed below. They are named after the places in Cameroon where they are collected or, in the case of Nigerian species, after some aspect of their colouration. Females are rather uniform in appearance, and unless otherwise stated the following identification tips are based on examination of the males.