Altolamprologus compressiceps

The Compressed Cichlid, Altolamprologus compressiceps, is a specialized predator from the rocky shorelines of Lake Tanganyika. Its most striking feature, the extreme lateral compression of its body, is a remarkable evolutionary adaptation. This physique allows it to navigate and hunt within the tightest rock fissures, preying on invertebrates and small fish that are inaccessible to other cichlids. Its sedentary nature and slow swimming speed are characteristics of an ambush predator; it conserves energy by waiting for prey to come within striking distance rather than actively pursuing it.

Setting up an aquarium for this species requires replicating its natural habitat. A tank with a sand substrate and extensive, stable rockwork creating a network of caves and narrow gaps is paramount. These structures provide essential shelter and territory demarcation. Water chemistry is non-negotiable and a primary reason for its 'medium' difficulty rating. Stable, highly alkaline, and very hard water is a must. Hobbyists often use crushed coral or aragonite sand as a substrate to help buffer the water and maintain the necessary high mineral content. Regular water changes are still vital to keep nitrates low, as Lake Tanganyika is a very stable, low-nutrient environment.

When considering tank mates, its slow movement and unique build make it surprisingly vulnerable to being bullied by faster, more aggressive cichlids, such as many Mbuna from Lake Malawi. Ideal companions are other Tanganyikan cichlids of similar size and temperament, like certain Julidochromis, Neolamprologus, or shell-dwellers that occupy a different niche. Its predatory nature ('triggered_by_very_small') means that any fish or invertebrate small enough to be viewed as prey, including most nano fish and shrimp, will be consumed.

Breeding is a fascinating process. They are secretive cave spawners. A female will select a tight crevice or a large, empty snail shell that is often too small for the larger male to enter. She lays her eggs inside and guards them fiercely. The male's role is to patrol the territory's perimeter. This behavior underscores the importance of providing a variety of cave sizes in the aquascape. Due to its low metabolism, a protein-rich carnivorous diet should be offered sparingly—feeding every other day is a common and effective strategy to prevent bloating and maintain peak condition. Several geographic color variants exist in the hobby, such as 'Gold Head', 'Kigoma', and 'Nangu', each offering a unique aesthetic.

Altolamprologus compressiceps is a cichlid endemic to the littoral rocky zones of Lake Tanganyika, Africa. The species name, 'compressiceps,' derived from Latin 'compressus' (compressed) and '-ceps' (head/body), aptly describes its defining morphological trait: extreme lateral compression. This morphology is a classic example of adaptive radiation, allowing the species to exploit a specific ecological niche as a specialized micropredator within narrow rock fissures, feeding primarily on small crustaceans and fish fry. Its sedentary behavior and low metabolic rate are energy-conservation strategies consistent with its ambush predation tactics.

The species' physiology is finely tuned to the unique limnological conditions of Lake Tanganyika—a highly stable environment characterized by elevated pH, high general hardness (GH) and carbonate hardness (KH), and significant total dissolved solids (TDS). In captivity, maintaining these parameters is critical for the organism's homeostasis, particularly osmoregulation. Failure to replicate this hydrochemistry can lead to chronic stress, weakened immune response, and shortened lifespan. The 'medium' difficulty in husbandry is a direct reflection of the need for precise and unwavering environmental control.

Behavioral ecology reveals a complex social structure. While territorial, A. compressiceps is not overly aggressive towards non-conspecifics that do not compete for its specific crevice-based niche. It is, however, an obligate carnivore with a defined prey-drive, making cohabitation with small species untenable. Its reproductive strategy is that of a secretive cave spawner with biparental care, although the female performs the majority of direct fry-guarding within a confined space. This behavior necessitates an aquascape with appropriate geological structures (caves, crevices, or large shells like Neothauma) to facilitate natural breeding cycles. The bioload factor, while numerically moderate, is composed of nitrogenous waste high in protein byproducts, necessitating a robust biological filtration system capable of maintaining near-zero ammonia/nitrite and very low nitrate levels, mimicking the oligotrophic nature of its native lake. While the species is listed as 'Least Concern' by the IUCN, numerous distinct geographic variants exist, and localized populations could face pressure from ornamental fish collection and localized habitat degradation.