Taxonomy & naming
Lamprologus mocquardi was described by the French ichthyologist Jacques Pellegrin in 1903, in a short note in the Bulletin du Muséum National d'Histoire Naturelle titled 'Cichlidé nouveau de l'Oubanghi appartenant au genre Lamprologus' — a new cichlid from the Oubangui (Ubangi) River, which fixes the type locality in that major right-bank tributary of the Congo. The genus Lamprologus had been erected twelve years earlier, in 1891, by the Dutch zoologist Louise Schilthuis for Lamprologus congoensis from Stanley (Malebo) Pool. A single synonym is recognized: Lamprologus obliquus Nichols & Griscom, 1917, described from Stanleyville (now Kisangani) and later sunk into mocquardi by Daget and colleagues in the CLOFFA checklist (1991). The species sits in the tribe Lamprologini, subfamily Pseudocrenilabrinae. Its genus has a tangled history: through much of the twentieth century 'Lamprologus' was a catch-all that swelled to dozens of Lake Tanganyika cichlids, but a series of revisions — Colombé & Allgayer (1985), Poll (1986), and decisively Stiassny (1997) — confined Lamprologus sensu stricto to the riverine cichlids of the Congo basin, moving the Tanganyikan species into Neolamprologus, Lepidiolamprologus, Altolamprologus and others. Roberts & Stewart's 1976 survey of the Congo rapids and Schelly & Stiassny's later work refined the riverine roster; the genus today holds nine valid species, of which mocquardi is among the most widely distributed.
Morphology
This is a small cichlid: FishBase gives a maximum of about 4.5 in total length, at the lower end of the 4.5–6 in range typical of the riverine Lamprologus. The body is elongate and laterally compressed, with a long-based dorsal fin whose spiny portion is well developed, rounded pelvic fins, and a rounded caudal fin — the classic build of a fish that lives close to the bed of a flowing river. Adults of both sexes develop a modest nuchal hump on the forehead. Ground colour is an unshowy brown; courting and dominant males carry rows of small, bright silvery dots scattered along the flanks and the unpaired fins, a trait that varies considerably between individuals, while females generally lack the silvery spotting. Faint vertical bars may appear, and during breeding the pattern darkens markedly, ripe females in particular sometimes turning almost black. Diagnostically, the genus is marked by 4–10 anal-fin spines, jaws bearing a band of fine unicuspid teeth with six to ten enlarged anterior canines, and ctenoid scales. Sexual dimorphism is real but subtle: males grow larger, carry the more pronounced hump and the silvery flecking, while females are plainer.
Habitat
Lamprologus mocquardi has one of the broadest ranges of any Congo Lamprologus, spanning the middle and upper reaches of the basin from Mbandaka upstream to the Upemba lakes. Its documented distribution takes in most of the Ubangi–Uele drainage, the lower Ruki and lower Mongala, the Itimbiri, the Ituri–Aruwimi, the Lindi–Tshopo, the Lomami, the cataracts at Wagenia (Boyoma) Falls near Kisangani, and the Lualaba and its tributary the Luvua up to the Upemba lakes on the Katanga plateau. Unlike most of its congeners, which are confined to the lower Congo near the Atlantic, mocquardi (with L. symoensi) is a fish of the deep interior. It is a rheophilic species — adapted to flowing water — and like other riverine Lamprologus it has a reduced swim bladder that lets it sink and hold position on the bottom of fast currents rather than fight to stay down. Its biotope is the rocky, oxygen-rich, flowing stretches of these rivers, where cracks and crevices between stones provide both feeding territory and spawning sites. The water of the Congo system in these reaches is generally soft and warm; conductivity in the wider basin runs low (often well under 120 µS/cm), pH ranges from mildly acidic to mildly alkaline near neutral, and temperatures sit broadly in the mid-20s Celsius. FishBase records the species across roughly 6°N to 5°S, an equatorial, tropical range.
Feeding
Lamprologus mocquardi is an insectivore. Like the other riverine Lamprologus it has a short, simple intestine — the gut of a carnivore rather than a plant- or detritus-processor — and forages over and among the rocks of its flowing habitat for aquatic insect larvae and other small invertebrates carried or sheltering in the current. FishBase's model-based trophic estimate places it near the top of the food web at a trophic level around 3.9, consistent with a predatory micro-invertebrate feeder rather than an omnivore. In the river community it occupies the rock-dwelling invertivore niche alongside other rheophilic cichlids such as Steatocranus, Teleogramma and Nanochromis, and various rapids-adapted catfishes and cyprinids, partitioning the crevice habitat with them.
Mating
Breeding has not been observed in the wild for any riverine Lamprologus, but the captive picture is consistent across the genus, and mocquardi conforms to it. These are monogamous fish that form stable pair bonds. Curiously for a pair-bonding cichlid, the partners do not usually share a single cave or hiding place; instead each holds its own refuge while staying close to its mate, so the pair occupies adjacent territories rather than a shared one. As spawning approaches both fish darken, the female often most dramatically. The male's role is largely territorial — defending the area around the spawning site — while the female commits to the cave itself. This loosely coordinated, two-territory arrangement, with the female doing most of the direct egg care, is the foundation of the species' breeding system.
Breeding
Lamprologus mocquardi is a monogamous substrate or cave spawner: the female lays a clutch of small, whitish eggs on the wall or ceiling of a crevice or cave and tends them largely on her own. Genus-typical clutches run up to about 400 eggs for a large female. The eggs hatch after roughly three days and the wrigglers, cryptically coloured to blend with the substrate, are kept inside the cave; they become free-swimming about six to seven days after hatching, once the yolk sac is consumed. For the first week of free swimming the pair actively shepherds the fry, but parental behaviour then shifts: rather than continuing to lead and herd the young, the parents increasingly defend the territory and simply tolerate the juveniles within it — a pattern shared with cave-brooding relatives such as Julidochromis and Teleogramma. The fry stay within the parents' territory for some four to six weeks before dispersing. No wild spawning of this particular species has been documented, so these details are drawn from observations of the species in captivity and of its close congeners.
In the aquarium
Within the genus, Lamprologus mocquardi is an upper-Congo fish that reaches the hobby far less often than lower-river species such as Lamprologus congoensis; it is best regarded as an occasional, intermediate-level aquarium fish rather than a commonly traded one. Where it or its near relatives have been kept, the husbandry is well understood. Because these are active, fast-moving rheophilic cichlids, a tank of at least 30 US gallons (about 30 US gal) is the practical minimum, and more swimming length is better. The defining requirement is to recreate a flowing, rocky riverbed: a sand substrate topped with a generous pile of rocks arranged to form caves and crevices, supplemented with waterlogged wood. Each fish should be able to claim its own refuge. Aquatic plants are not part of the natural habitat and are not needed. Strong, well-oxygenated water movement is important — these fish come from current — so brisk circulation and surface agitation should be provided, along with frequent water changes to keep the water clean.
Water chemistry is forgiving. The natural environment is soft and warm, but the fish are hardy and adapt to a wide span: a pH around neutral is ideal, yet they do well in both mildly acidic and mildly alkaline water, so chemistry is a secondary concern compared with cleanliness and flow. A temperature in the mid-20s Celsius (roughly 75–79 °F / 75–79 °F) suits them. Feeding is straightforward for an insectivore — a varied diet of meaty frozen and live foods (bloodworm, brine shrimp and similar) plus good-quality prepared foods. Tankmates should be chosen to respect the species' need to hold territory: avoid large, boisterous cichlids that would bully them off their caves, and pair them instead with other riverine West/Central African species of similar temperament. They are easy to breed once a compatible pair is settled, provided natural-looking caves are available; the fry are small but readily raised on baby brine shrimp, microworms or vinegar eels, and several generations can coexist in a roomy, rocky tank.
Conservation
The IUCN Red List assesses Lamprologus mocquardi as Least Concern (assessed 16 February 2009 by T. Moelants, published 2010). The rating reflects the species' very wide distribution across the middle and upper Congo basin — it occurs in the Democratic Republic of the Congo, the Central African Republic and the Republic of the Congo — and the absence of any identified basin-wide threat to it. The population trend is listed as unknown, and the species carries no CITES listing. As a widespread riverine generalist it is far less exposed than the basin's many narrow-range endemics. That said, the Congo system as a whole faces mounting pressures — deforestation in its catchments, expanding hydropower and dam development on the mainstream and tributaries, artisanal and industrial mining with attendant pollution, and intensifying fisheries — and the rapids-and-rocks habitats that the riverine Lamprologus depend on are precisely the stretches most altered by damming. None of these is documented as a present danger to this particular species, but they are the backdrop against which its long-term status should be read.