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Taxonomy & naming

Cyprichromis zonatus was described in 2002 by Tetsumi Takahashi, Michio Hori and Kazuhiro Nakaya in the journal Copeia, on the basis of 21 specimens collected at Kasenga on the Zambian coast (holotype HUMZ 175834, taken at 11 m depth). The same authors are well known for later splitting the deepwater 'frontosa' into Cyphotilapia frontosa and C. gibberosa. Eschmeyer's Catalog of Fishes lists the name as valid and unchanged since publication.

The genus name combines Latin cyprinus (carp) with the Greek chromis, a generic fish name; the species epithet zonatus is Latin for 'banded' or 'belted', referring directly to the vertical bars on the dorsal half of the male's body. Cyprichromis belongs to the tribe Cyprichromini, a small group of open-water planktivores endemic to Lake Tanganyika that also includes Paracyprichromis. At the time of its description C. zonatus was the fourth species recognized in the genus; a fifth, the similar C. coloratus, followed in 2006. In the hobby it circulates under regional collection-point labels and the trade name 'zebra', a nod to the same striping the scientific name records.

Appearance

This is a small cichlid: the type series tops out around 3.4 in (8.6 cm) standard length for males and about 3.2 in (8.1 cm) for females, so total length including the tail runs a little larger. The body is fusiform and laterally compressed, a streamlined shape suited to a life spent hovering and darting in open water rather than threading through rocks.

The diagnostic feature is the banding. Males carry three to four broad, dark vertical bars across the upper half of the body beneath the dorsal-fin base, the front-most one fainter than the rest; these bars are absent or barely visible in every other Cyprichromis, which is what makes the species recognizable at a glance underwater. Breeding males are otherwise yellowish, washed bluish or slightly dusky along the back, with several yellow lines following the scale rows on the lower body, a bluish dorsal fin, a yellow-and-blue anal fin, and a dark gray pelvic fin tipped in yellow. Females and non-breeding fish are drabber, with indistinct bars, muted fins and no yellow pelvic tip. Fin counts (13-15 dorsal spines, 14-16 dorsal soft rays, three anal spines) and 36-38 vertebrae round out the formal description.

Range & habitat

Cyprichromis zonatus is a Lake Tanganyika endemic with a narrow distribution: the IUCN places it along the southeastern coast from Cape Mpimbwe in Tanzania south to Cape Kaku in Zambia, with documented localities at Kasenga, Chituta Bay and west to Cape Chaitika. This is a far smaller range than the lake-wide 'sardine cichlid' C. leptosoma occupies, and it is part of why the species reads as a southern Tanganyika specialty in the trade.

The fish lives over rocky bottoms but not on them. Individuals and schools typically hold 3-16 ft (1-5 m) above the substrate, across a depth band of roughly 30-100 ft (9-30 m), and are most abundant around 65 ft (20 m). Lake Tanganyika's water is hard and alkaline year-round, warm and remarkably stable, behaving like an inland sea; the open, oxygen-rich water column over reef is the habitat this fish is built for. It is the rock that anchors the community, even though C. zonatus rarely touches it.

Ecology & diet

Cyprichromis are zooplanktivores, and C. zonatus is no exception: it picks small crustaceans and other drifting plankton from the water column with a small, protrusible mouth, a feeding mode shared across the Cyprichromini. FishBase estimates a trophic level near 3.5, consistent with a small invertebrate predator rather than a herbivore or piscivore.

Ecologically these sardine cichlids occupy the same niche above the reef that their open-water shape implies, and they are a textbook example of Tanganyika's mixed-species schools. Females and sub-adult males of C. zonatus join shoals that can number into the thousands and frequently mingle with congeners; published observations from Zambia describe C. zonatus schooling at intermediate depths alongside C. leptosoma, the newer C. coloratus and Paracyprichromis brieni, with the species sorting out by depth as deeper water gives way to C. pavo and P. nigripinnis. That safety-in-numbers shoaling is a defense against the lake's predatory cichlids and birds, and the cyprichromines in turn form an important prey link in the littoral and sublittoral food web.

Behavior & breeding

The most striking thing about Cyprichromis behavior is how they hold territory. Mature males do not defend rock; they defend a column of open water, typically above a large boulder in 50-80 ft (15-25 m) of water, holding station and displaying to passing females while warding off rival males from above, below and every side. Observers have compared this three-dimensional, lek-like spacing to that of marine anthias.

Like nearly all Tanganyikan cichlids, C. zonatus is a maternal mouthbrooder. In leptosoma and its close relatives, spawning happens in midwater: the female drops large eggs one at a time and snaps each back into her mouth, fertilizing by mouthing the male's anal fin, so the whole sequence unfolds without ever settling on the substrate. The female then broods the developing young in her buccal cavity for several weeks. Clutches are small for a cichlid, generally in the range of about 6-15 eggs, and the fry are correspondingly large at release. C. zonatus's own spawning has been less directly documented than that of leptosoma, but its anatomy and territorial system point to the same midwater strategy.

In the aquarium

Cyprichromis are intermediate-level Tanganyikans, and the central rule is the same one experienced keepers repeat for the whole genus: open water and numbers. Plan on a tank at least 4 ft (120 cm) long, and honestly a 5-6 ft footprint serves them far better. Across cichlid forums, keepers of the closely related leptosoma 'jumbo' and 'Utinta' report that a 4-foot tank is too small to spread out male aggression: dominant males commandeer the open water and harass subordinates, which can pine away and die, and a recurring symptom is a white spot on the eye in stressed fish. The community-tested fixes are a larger tank, plenty of vertical structure such as slate set against the back glass for refuge, and either a single male or enough males (with more females) to diffuse the aggression rather than an awkward in-between number. A common starting ratio is roughly three males to seven females in a group of ten or more.

Water should be hard and alkaline, matching the lake: pH well above neutral (keepers run roughly 8.0-8.5), warm temperatures around the mid-70s F (about 24-26 C), high oxygenation and good flow, since Tanganyikans tolerate low oxygen poorly. Feed small meaty foods that suit a zooplankton specialist's small mouth, watching that shy or newly introduced fish actually get their share. Good tankmates are calmer Tanganyika biotope fish such as Altolamprologus calvus and compressiceps, shell-dwellers and sand-sifting Xenotilapia given enough separation; keepers warn against territorial, vegetarian-diet Tropheus and against crowding the open water these fish need to display. One more practical caution from the hobby: mixed-origin Cyprichromis are easy to confuse and can hybridize, so buy from a source that keeps collection variants separate and know exactly what you have.

Conservation

The IUCN Red List assesses Cyprichromis zonatus as Least Concern (assessment by Fermon, dated 2014, published in the 2025 update), with an unknown population trend. The justification is straightforward: it is endemic to Lake Tanganyika but locally abundant in large schools, and no major widespread threats specific to it have been identified. The assessors note that capture for the aquarium trade could matter at particular collection sites, but because the species occurs in such large shoals this is judged unlikely to have a significant impact; bycatch from illegal non-selective fishing gear and sedimentation from shoreline deforestation are flagged as more general concerns. So the honest headline is that the fish itself is not in trouble, even as the lake it depends on is under real strain.

That lake-level strain is well documented. Lake Tanganyika has been warming and stratifying more strongly, which suppresses the deep mixing that fertilizes its surface waters; O'Reilly and colleagues (2003, Nature) inferred from sediment cores that primary productivity may have fallen by roughly 20%, implying on the order of a 30% drop in fish yields, and Cohen and colleagues (2016, PNAS) found that reduced mixing has shrunk oxygenated benthic habitat by about 38% in their study areas, accompanying declines in commercially important fishes and endemic molluscs. Sedimentation from deforestation continues to degrade the rocky littoral that structures shallow-reef communities. These basin-scale pressures bear most heavily on the lake's huge pelagic clupeid-and-Lates fishery, which feeds four nations, and on deep benthic species; a planktivore of the upper reef like C. zonatus is more exposed to warming-driven losses in plankton productivity and to nearshore sedimentation than to the offshore net fishery. Governance is shared by the four riparian states through the Lake Tanganyika Authority, which has trialed a May-August fishing closure that would, if maintained, give shoaling species like this one a seasonal window to reproduce. The species is secure today; its long-term outlook is tied to whether the lake's productivity and shoreline hold up.

Cyprichromis zonatus

About this species