Easy to intermediate
Chocolate Cherry Shrimp (Neocaridina davidi)
18–26°C · pH 6.5–8 · 30L
£13.99
The Black Pearl Calvus (Altolamprologus calvus) is a striking, dark Lake Tanganyika cichlid with a distinctive compressed body and pearl-flecked sheen. A moderate-care hard-water predator for specialist Rift Lake aquariums. Ordered with live arrival guarantee and tracked UK delivery.
Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size variant above for the actual shipping size. Photos are AI-enhanced, so the animal may show subtle colour or marking differences.
Altolamprologus calvus black pearl
Black Pearl Calvus bond and breed in male/female pairs. Buying a pair gives them the social structure they need — and you get a better price per fish.
The Black Pearl Calvus (Altolamprologus calvus) is a striking, dark Lake Tanganyika cichlid with a distinctive compressed body and pearl-flecked sheen. A moderate-care hard-water predator for specialist Rift Lake aquariums. Ordered with live arrival guarantee and tracked UK delivery.
Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size variant above for the actual shipping size. Photos are AI-enhanced, so the animal may show subtle colour or marking differences.
Cichlids are one of the most diverse fish families in the hobby. From tiny apistogrammas to massive oscars, this guide covers the basics of keeping them well.
Maintain these water conditions for optimal health and vibrant colors
The Black Pearl Calvus (Altolamprologus calvus) is one of the most distinctive Lake Tanganyika cichlids you can add to a Rift Lake aquarium, and a standout among the tropical fish for sale UK hobbyists seek out for genuine character. This striking African cichlid combines a deep charcoal-to-black body, subtle vertical barring, and a famously compressed shape that lets it slip into rocky cracks and shell beds in search of food. If you want to buy tropical fish UK aquarists respect for intelligence, unusual hunting behaviour, and long-term character, this species deserves a close look. Adults reach around 14 cm, can live up to 10 years, and do best in hard, alkaline water at a tropical temperature of 24-27°C. Care is moderate: not difficult once established, but the fish does need the right aquascape, stable chemistry, and carefully chosen tank mates.
Our detailed photos show the sleek body profile, dark pearl sheen, and predatory cichlid posture that make the Black Pearl Calvus such a favourite among keepers of Lake Tanganyika cichlid UK species. For aquarists searching for tropical fish for sale online, looking to buy live fish online UK, or trying to find the best place to buy tropical fish online, this is a fish that rewards patience with years of fascinating behaviour. It is not a typical community fish, but in the right setup it becomes the centrepiece of a carefully planned Tanganyikan display. New to keeping cichlids? Our cichlid care guide is a useful companion reference for water chemistry, aggression management, and tank design.
Altolamprologus calvus is part of the diverse cichlid family and sits among the specialist predators of Lake Tanganyika. In the aquarium hobby, Calvus and its close relative Altolamprologus compressiceps are admired for their laterally compressed bodies, slow growth, and highly observant behaviour. The Black Pearl is a particularly dark, pearl-flecked form of A. calvus, sought after by keepers who want an authentic, rare-looking African cichlid with true Rift Lake character.
The Black Pearl Calvus comes from Lake Tanganyika in Africa, one of the oldest and deepest freshwater lakes on Earth. This huge rift lake stretches across Tanzania, the Democratic Republic of the Congo, Burundi, and Zambia. In the wild, Altolamprologus calvus inhabits rocky shorelines, broken stone fields, and areas littered with empty snail shells and crevices. Recreating that natural setting is the key to a successful Black Pearl Calvus Tanganyika setup.
Unlike open-water fish, Calvus spend much of their time weaving through rock piles, inspecting narrow gaps, and ambushing tiny prey. Their body shape is not just attractive; it is a survival tool. The compressed profile lets them enter spaces other predators cannot reach. This is exactly why Calvus are famous for picking off fry and small invertebrates around shells and rockwork, and why some keepers value them for thinning out pest snails and surplus fry rather than as a true clean-up fish.
Lake Tanganyika water is mineral-rich, hard, and alkaline, so a stable, mature tank ecosystem matters far more than chasing random additives. This is not a soft-water Amazonian fish, and that distinction shapes your filtration, substrate, and decor choices. Keepers who have kept other African cichlids will recognise the hardness and high pH, but Tanganyika species like this one often show more specialised territory use and feeding behaviour.
Many hobbyists searching for a freshwater cichlid for UK aquariums, or specifically a Lake Tanganyika cichlid UK stockists supply, want a fish that looks unusual without needing extreme care. The Black Pearl Calvus fits that niche well. It is more refined than many boisterous mbuna, less bulky than large predators, and ideal for a carefully structured rocky aquarium. Note that this species is strictly an indoor heated aquarium fish and must never be kept in an unheated tank or outdoor pond.
Mimicking the natural habitat with stacked rockwork, caves, shell beds, and open patrol lanes improves confidence and reduces stress. In our experience, Black Pearl Calvus show stronger colour and more natural stalking behaviour when they can move between shadowed crevices rather than sitting in a bare tank.
A proper setup is the difference between a shy, washed-out fish and a confident, beautifully marked adult. The minimum tank size for Black Pearl Calvus is 200 litres, but a larger aquarium is better for a pair or a mixed Tanganyika community. For a single specimen or bonded pair, think in terms of footprint as much as volume: a tank around 100 cm long is a sensible starting point, while a small 50-60 cm aquarium is too cramped long term, even though juveniles look tiny in shop tanks.
The right tank size depends on the species, and for Black Pearl Calvus you should aim for 200 litres minimum, rising to 240-300 litres if you mix it with other Tanganyikans. The fish is slow-growing but territorial, and the extra room helps break lines of sight. For a pair kept with compatible companions, an aquarium around 120 cm in length is ideal.
The ideal temperature for Black Pearl Calvus is 24-27°C, with 25-26°C a reliable target for everyday keeping. This species prefers the warmer end of a Rift Lake setup but not excessive heat, so a steady, accurate temperature matters more than chasing a precise figure. For water chemistry, keep pH between 7.5 and 9.0 with hardness around 10-20 dGH. The water should be firmly alkaline, and stable values matter more than the highest possible number. A dependable heater and a regular test routine keep that narrow range steady.
A strong, mature filter is vital because carnivorous cichlids produce substantial waste. Your filter and heater should provide steady turnover and stable warmth without blasting the fish with excessive current. Use a quality external canister or an oversized internal filter with plenty of biological media. When planning a complete setup, include a dependable heater, an accurate thermometer, and a test kit from day one. Place the heater where the flow carries warmth evenly through the tank, usually near the filter outlet, and verify the temperature with a separate thermometer. A reading that drifts too low can suppress appetite, while water that runs too hot increases stress and lowers dissolved oxygen.
Fine sand or smooth gravel works best. Add rock piles, caves, narrow crevices, and some shell beds. This is not a fish that needs heavy planting, but if you want greenery, choose hardy plants such as Anubias, Java fern, or Vallisneria attached to rockwork so they tolerate the hard, alkaline water. Use plant food sparingly and only if your plants genuinely need it. Lighting should be moderate rather than harsh: too much bright light over a bare tank makes Calvus nervous, while dark rock, pale sand, and shadowed zones help the fish display stronger colour. The essentials for a first Rift Lake display are space, rockwork, stable alkalinity, efficient filtration, and a fully mature cycle.
Always cycle the tank for 4-6 weeks before adding Black Pearl Calvus. A mature filter is far more important than decorative extras. Compact beginner kits and small starter tanks are quickly outgrown by this species, so start with adequate volume from the outset.
The Black Pearl Calvus diet is carnivorous. In nature, these fish take small crustaceans, insect larvae, fry, and tiny fish they trap among rocks and shells. In the aquarium, the best results come from a varied menu of high-protein foods rather than generic flake. Good staples include quality cichlid pellets, frozen mysis, krill, brine shrimp, and other finely sized meaty foods. Because Calvus are deliberate, methodical feeders, avoid housing them with frantic surface feeders that snatch everything first.
Feed a small sinking carnivore pellet once or twice daily. This gives structure to the diet and helps maintain condition. Supplement with frozen foods several times a week. Juveniles need smaller, more frequent meals; adults do well on controlled portions. Stable, well-filtered water keeps appetite strong and predictable.
Frozen brine shrimp, cyclops, chopped prawn, and mysis are excellent for colour and breeding condition. Live foods can be offered occasionally from safe, parasite-free sources. Avoid fatty mammal meats and oversized foods that encourage bloat. This is a hunter, not a grazer, so it does not need the constant algae-based feeding that herbivorous or bottom-feeding species rely on.
Feed juveniles 2-3 small meals daily and adults 1-2 measured meals, giving only what they can finish in a minute or two. Uneaten food quickly degrades water quality in a hard-water cichlid setup, and overfeeding is a common root cause of nuisance algae and cloudy water. Good feeding discipline does far more for water clarity than any single "cleaner" fish. Importantly, Black Pearl Calvus are predators, not algae eaters or tank cleaners, so never rely on them to maintain the aquarium. Clean tanks come from husbandry, not from expecting one fish to do the work.
| Time | Food | Amount |
|---|---|---|
| Morning | Small carnivore pellet | Only what is eaten in 1-2 minutes |
| Evening | Frozen mysis or brine shrimp | Small pinch per fish |
Overfeeding causes ammonia spikes, cloudy water, and avoidable health issues. If you notice a greasy surface film, rising nitrate, or leftover food collecting between rocks, reduce portions immediately and review your maintenance routine.
The Black Pearl Calvus has one of the most recognisable silhouettes in the cichlid world. Adults reach about 14 cm but appear larger thanks to their tall body and elongated fins. The body is strongly laterally compressed, almost blade-like from the front, with a sloping forehead and an alert, predatory expression. This unusual shape is exactly why many hobbyists read a Black Pearl Calvus care guide before buying.
Colour ranges from smoky grey to rich black-brown with metallic pearl flecking and subtle vertical bars. In good conditions the scales shimmer with a dark satin effect, especially against pale sand and dark rock. Our photos show the intense chocolate-black sheen that develops with stable water chemistry, subdued lighting, and a high-quality carnivore diet. The fins are elegant rather than flashy, adding to the fish's stealthy look.
Males are usually larger, deeper-bodied, and more imposing, while females stay smaller and often show a rounder profile when mature. Because growth is slow, young fish may not show obvious sex differences early on, which is one reason a true Black Pearl Calvus breeding pair is harder to form than with many common cichlids. Patience is very much part of this fish's appeal.
For display value, this species suits a larger, well-structured rocky tank best. The dark body contrasts beautifully with shell beds, pale limestone, and sparse hardy planting. A planted Tanganyikan layout is possible if the plants tolerate hard water, but the fish truly shines in a rocky biotope where its hunting posture and compressed body shape are fully on show.
The key to Black Pearl Calvus tank mates is that this species is not wildly aggressive, but it is predatory and territorial. Suitable companions must be too large to be eaten, calm enough not to harass it, and compatible with hard, alkaline water. The best matches are other Lake Tanganyika species with similar water needs and measured temperaments.
Good companions include other medium Tanganyikan cichlids, selected shell dwellers in larger aquariums, and species that occupy different zones of the tank. This is not a standard soft-water community fish, so a Black Pearl Calvus community tank should really be a specialised Rift Lake community rather than a mixed tropical assortment.
For aquarists planning a hard-water cichlid collection, related Rift Lake fish such as Kiriza Yellow Cichlid - Tropheus Moorii, Orange I Blunthead Cichlid - Tropheus, Aulonocara Sp Neon Red Calico Peacock, Rubin Red Peacock Cichlid - Aulonocara, Aulonocara kandeense, and Yellow Elongatus Cichlid - Chindongo Elongatus illustrate the temperament and layout choices worth considering. Not all are direct Tanganyika matches, but they help experienced keepers compare behaviour and aquascaping when planning compatible companions.
Avoid very small fish such as tiny tetras, guppies, and delicate nano species. Soft-water community fish like tetras and guppies prefer cooler, more acidic conditions and are poor companions in an alkaline Tanganyika setup, and small fish or shrimp may simply be treated as food. This is also not the right tank for large oddball "tank busters" or aggressive monsters; the Black Pearl Calvus is subtle and strategic, and is best appreciated in a natural rocky display alongside measured, similarly sized cichlids.
In a 200-litre tank, keep a single pair with carefully structured territories. In 300 litres or more, a pair can be combined with shell dwellers or one other compatible Tanganyika group if the rockwork is extensive. Importantly, this is not a schooling fish, so keep it as a pair or a small group only in large, expertly arranged aquariums rather than as a loose shoal.
| Species | Compatible? | Notes |
|---|---|---|
| Kiriza Yellow Cichlid - Tropheus Moorii | ⚠️ Caution | Similar hard-water needs, but Tropheus have different feeding and social demands. |
| Aulonocara Sp Neon Red Calico Peacock | ⚠️ Caution | Possible only in large, carefully managed hard-water setups; not a classic Tanganyika pairing. |
| Small tetras or guppies | ❌ Avoid | Too small, wrong water chemistry, and may be hunted. |
Good compatibility also depends on maintenance. Master regular tank cleaning and water-change routines before adding multiple cichlids, because stable water quality reduces aggression. If you are still building confidence with your first aquariums, this species is better as a second or third cichlid project than as a first-ever fish.
Always quarantine new cichlids in a separate heated tank for 2-4 weeks before introducing them. Quarantine protects established fish, lets you observe feeding response, and prevents one stressed newcomer from upsetting the whole hierarchy.
Breeding Black Pearl Calvus is considered difficult, mainly because the fish grows slowly, sexes are hard to distinguish when young, and pairs may take time to settle. Even so, successful spawning is possible in a mature species tank or a dedicated breeding setup. To form a true breeding pair, start with a small group of juveniles and allow a pair to form naturally over time.
Use at least 200 litres, though more space helps. Provide narrow caves, empty snail shells, and tight rock crevices where the female can retreat. Keep the temperature around 25-27°C, pH at 8.0 or above, and the water very clean, aiming for zero ammonia, zero nitrite, and nitrate under 20 ppm.
The female typically chooses a cramped spawning site, often one the much larger male cannot fully enter, fertilising the eggs from outside. Courtship is subtle compared with more flamboyant cichlids. Once eggs are laid, the female guards them while the male patrols nearby. With Calvus the eggs are usually hidden deep inside a cave or shell rather than openly displayed, so spawning can easily go unnoticed.
Hatching time varies with temperature, and fry usually stay hidden for some time after hatching. Newly free-swimming fry can be fed baby brine shrimp and finely crushed fry foods. Growth is slow, so this is not a species that produces saleable juveniles quickly. Gentle filtration and excellent water quality are critical throughout this stage.
The main problems are pair incompatibility, egg predation, and poor fry survival in mixed tanks. A species-focused breeding tank gives the best chance of success. Breeding specialist Tanganyika cichlids is advanced fishkeeping at its most rewarding: success comes from precision and patience, not luck.
Offer multiple cave sizes and shell options rather than a single spawning site. In our experience, females choose the tightest, most secure cavity available, and pair stability improves when the female can retreat fully out of the male's line of sight.
Shoppers comparing Tanganyikan cichlids often weigh the Black Pearl Calvus against more active, colourful alternatives. The right choice depends on whether you value subtle predatory behaviour, an unusual body shape, and long-term character over fast movement and bright open-water display. Its closest relative, Altolamprologus compressiceps, shares the same compressed shape and ambush lifestyle but tends to be slightly deeper-bodied.
| Feature | Black Pearl Calvus | Kiriza Yellow Cichlid |
|---|---|---|
| Max Size | 14 cm | 12-14 cm |
| Care Level | Moderate | Moderate to advanced |
| Temperature | 24-27°C | 24-27°C |
| Best For | Rocky ambush predator displays | Active colony-style cichlid setups |
| Feature | Black Pearl Calvus | Thorichthys Maculipinnis |
|---|---|---|
| Water Type | Hard, alkaline | Neutral to slightly alkaline |
| Temperament | Semi-aggressive, predatory | Assertive but more open-water |
| Aquascape | Rocks, caves, shells | Open areas with wood and substrate |
| Look | Dark, compressed, stealthy | Brighter, broader-bodied |
| Best For | Tanganyika specialists | General cichlid keepers |
If you want a fish with a unique profile and intelligent hunting behaviour, choose the Black Pearl Calvus. If you prefer more constant activity or a brighter open display, compare it with Thorichthys Maculipinnis - Elliot'S Cichlid -, Guianacara Dacrya - South American Cichlid, or Yellow Elongatus Cichlid - Chindongo Elongatus. Among Tanganyikan cichlids in the UK, the Black Pearl Calvus stands out for stealth and structure rather than speed.
A healthy Black Pearl Calvus is alert, well-balanced in the water, interested in food, and shows clean fins with no clamped posture. Colour should be rich rather than washed out, although newly introduced fish are often shy at first. Most problems stem from unstable water, poor diet, or stress from bullying tank mates, not from the species being inherently delicate.
Watch for white spot, bacterial fin damage, a hollow belly from internal parasites, and stress-related darkening or hiding. Tropical fish tank diseases often appear first after transport or when new fish are added without quarantine. If you notice flashing, heavy breathing, or refusal to feed, test the water immediately.
Knowing how to test your aquarium water is essential, so check ammonia, nitrite, nitrate, pH, and temperature regularly. The honest list of chemicals you actually need is short: a good dechlorinator, possibly Rift Lake buffers if your tap water is too soft, and targeted medications only when a specific problem is diagnosed. Random dosing usually causes more harm than good. Routine care also means weekly partial water changes done properly, matching temperature, dechlorinating the new water, and avoiding large, sudden chemistry swings. Cloudy, smelly, or green water is almost always caused by overfeeding, immature filtration, excess light, or inadequate maintenance rather than the fish itself.
Never medicate blindly. Treat the cause first by testing water and observing behaviour. Copper-based medications must be used with extreme care and only when appropriate, especially in mixed systems containing sensitive species or invertebrates.
Black Pearl Calvus are observant, strategic fish rather than constant swimmers. They hover near rock faces, inspect crevices, and make sudden, precise movements when food appears. New keepers sometimes mistake this for shyness, but it is normal predatory behaviour. Given secure cover, the fish becomes bolder and spends more time in view.
They are best kept as a pair or a carefully managed small group, not as a loose shoal, and territorial behaviour increases around caves and spawning sites. In a well-designed tank they spend much of their time in the middle and lower rock zones, patrolling more widely once comfortable. This makes them a fascinating step up for aquarists moving beyond easy beginner fish and into specialist cichlid keeping.
To see the most natural behaviour, provide layered rockwork, subdued lighting, and calm tank mates that do not constantly rush the front glass. This species rewards patient observation: it is not flashy every second of the day, but few fish match the quiet confidence of a settled adult Calvus stalking through a Tanganyikan rockscape.
Our Black Pearl Calvus are selected for body shape, condition, and strong dark base colour rather than simply listed as another generic cichlid. That matters with this species, because quality juveniles grow slowly and good structure early on usually leads to better adult presence. Ordering from a specialist online aquatics shop gives you access to Rift Lake stock that rarely appears in general pet chains.
Before dispatch, fish are observed for feeding response and general health, then packed in insulated boxes with appropriate seasonal protection, including heat packs in colder weather. This care matters for hard-water cichlids that dislike sudden temperature drops. We include acclimation guidance so the move into your aquarium is as smooth as possible. The Black Pearl Calvus is a long-term Rift Lake cichlid for aquarists who want structure, behaviour, and authenticity rather than an impulse buy, so specialist sourcing makes a real difference.
If you are ready to buy live fish online in the UK with a clear plan in mind, this species is a rewarding choice. Order your Black Pearl Calvus today with confidence if you want a distinctive Lake Tanganyika centrepiece that will mature into one of the most characterful fish in your aquarium.
Planning a full hard-water setup? Compare your Black Pearl Calvus with Kiriza Yellow Cichlid - Tropheus Moorii for a more active Tanganyika display, or look at Orange I Blunthead Cichlid - Tropheus if you enjoy colony-style cichlids with bold presence. For Malawi-style contrast, Rubin Red Peacock Cichlid - Aulonocara and Aulonocara Sp Neon Red Calico Peacock show how different Rift Lake colour and behaviour can be. If you are comparing broader cichlid options, Guianacara Dacrya - South American Cichlid and Thorichthys Maculipinnis - Elliot'S Cichlid - offer useful alternatives for different water chemistry and aquascaping styles.
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