A striking, highly intelligent cichlid native to the island of Madagascar. Commonly known as the Starry Night Cichlid due to its velvety jet-black body covered in brilliant iridescent white, blue, or gold spots. They possess a large mouth and are piscivorous (fish-eating), making them a threat to smaller tank mates. They are robust, aggressively territorial, and best kept as solitary showpiece fish or in heavily managed, large cichlid communities.
Black Diamond Cichlid At a Glance
Black Diamond Cichlid Tank Requirements
Will Black Diamond Cichlid fit in your tank?
Care guides tell you what Black Diamond Cichlid needs, the next question is whether your tank can safely provide it. Test Black Diamond Cichlid against your tank size, maintenance needs, and the fish you already keep before you buy.
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Black Diamond Cichlid Water Parameters
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Black Diamond Cichlid Temperament & Compatibility
Black Diamond Cichlid Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Male (Adult)
Adult males are massively robust, reaching up to 28cm (11 inches). They develop longer pelvic fins, a steeper forehead profile, and often a prominent nuchal hump as they mature. Highly territorial.
Differs in 1 trait from base species
Also known as: Bull Male, Large Polleni
Female (Adult)
Females are significantly smaller (usually maxing out around 15-18cm) and have a more rounded, sloping head without the nuchal hump. Slightly less aggressive than males but still predatory.
Differs in 4 traits from base species
Also known as: Female Polleni
Juvenile (Grow-out)
Young Polleni are typically mottled brown or grey before darkening into their spectacular jet-black adult coloration at around 3-4 inches. They grow rapidly and will quickly outgrow small grow-out aquariums.
Differs in 6 traits from base species
Also known as: Baby, Juvenile Starry Night
Black Diamond Cichlid Care Guide Summary
The Black Diamond Cichlid, scientifically known as Paratilapia polleni, belongs to the Cichlids - African family group. Adults reach a maximum size of approximately 28 cm and have a compressed body shape with a moderate growth rate. Classified as aggressive, this species primarily occupies the mid-level and bottom zones of the aquarium and produces a high level of biological waste.
To thrive, the Black Diamond Cichlid requires a freshwater only aquarium with a minimum volume of 280 litres and a tank length of at least 120 cm. Water temperature should be maintained between 24°C and 28°C, with a pH range of 6.5–8 and a general hardness of 5–20 dGH. A moderate water flow is preferred.
Due to its specialist needs, the Black Diamond Cichlid is best suited for fishkeepers who can provide a carefully planned setup. This species is available in 3 varieties: Male (Adult), Female (Adult), and Juvenile (Grow-out). Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.
Black Diamond Cichlid Habitat Setup
When setting up an aquarium for the Black Diamond Cichlid, a moderate water flow best suits their natural preferences. Because this species occupies the mid-level and bottom zones, the aquarium layout should prioritise open swimming space in the centre of the tank for free movement and sufficient floor space with hiding spots among rocks, wood, or dense planting. Useful additions include a sand substrate to accommodate their sifting behaviour, smooth gravel or rounded substrate to protect their sensitive barbels, and driftwood, which can serve as both a hiding place and a dietary supplement. Keepers should note that expect substrate disturbance, so lightweight décor should be secured.
Black Diamond Cichlid Compatibility Notes
Classified as aggressive, the Black Diamond Cichlid is best housed alone, as they do not tolerate others of their kind in confined spaces. When choosing tankmates, any fish small enough to fit in its mouth will likely be eaten, conspecific aggression can be intense, especially in smaller tanks, territorial behaviour may cause issues if hiding spots or floor space are limited, and their energetic swimming style may stress more sedentary or timid species. Selecting tankmates that favour different water layers from the mid-level and bottom zones can help reduce competition and territorial overlap.
Black Diamond Cichlid Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Black Diamond Cichlid.
75 Gallon Standard
90 Gallon Standard
125 Gallon Standard
150 Gallon High
180 Gallon Standard
350 Liter (120cm Deep)
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Frequently Asked Questions About Black Diamond Cichlid
How big does Black Diamond Cichlid get?
Black Diamond Cichlid (Paratilapia polleni) typically reaches a maximum adult size of approximately 28 cm. They have a compressed body shape and a moderate growth rate.
What tank size does Black Diamond Cichlid need?
A minimum aquarium volume of 280 litres and a tank length of at least 120 cm are recommended for Black Diamond Cichlid. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Black Diamond Cichlid need?
Black Diamond Cichlid thrives in freshwater only conditions with a temperature range of 24–28°C, a pH between 6.5 and 8, and a general hardness of 5–20 dGH. A moderate water flow is preferred.
Is Black Diamond Cichlid peaceful or aggressive?
Black Diamond Cichlid is classified as aggressive with an aggression score of 8 out of 10. Careful tankmate selection is essential to avoid conflict.
Can Black Diamond Cichlid live with others of its kind?
No. Only one Black Diamond Cichlid should be kept per tank. Keeping multiples in the same aquarium typically results in aggression and stress.
Does Black Diamond Cichlid have any special tank requirements?
Yes. Black Diamond Cichlid benefits from sand (sifters), driftwood (digestion/hiding), and smooth gravel (sensitive barbels) in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Plants That Suit Black Diamond Cichlid
These plants pair well with Black Diamond Cichlid based on shared water preferences, layout fit, and how likely they are to hold up in the same aquarium.
Afzel's Anubias
Anubias afzelii
Anubias Barteri
Anubias barteri
Belinda's Buce
Bucephalandra belindae
Buce Motleyana
Bucephalandra motleyana
Congo Anubias
Anubias heterophylla
Crepidomanes Fern
Crepidomanes auriculatum
Fish Similar to Black Diamond Cichlid
Duboisi Cichlid (Tropheus)
Tropheus duboisi
An iconic Lake Tanganyika cichlid famous for its dramatic life-stage color change. Juveniles are jet black with brilliant white polka-dots, while adults develop a blue head and a distinctive yellow or white vertical band across a dark body. They are highly aggressive toward their own kind and must be kept in large colonies (10+) to disperse aggression. They are strict herbivores that require a specialized diet to avoid fatal digestive issues.
Cuban Cichlid
Nandopsis tetracanthus
A striking, highly aggressive predatory cichlid native to the rivers and lakes of Cuba. They are known for their spectacular black and white 'mosaic' or 'tiger' patterning, which becomes incredibly vivid during breeding. Best kept by experienced aquarists due to their extreme territoriality, potential size, and need for hard, alkaline water. They are also known to be naturally euryhaline, tolerating brackish conditions.
Horei Cichlid
Ctenochromis horei
A robust and highly aggressive haplochromine cichlid native to Lake Tanganyika. Known for its striking coloration and dynamic, albeit violent, territorial behavior. Adults are opportunistic predators and piscivores. They are maternal mouthbrooders, and males are fiercely intolerant of other males. They require hard, alkaline water.
Three-striped Dwarf Cichlid
Apistogramma trifasciata
A stunning dwarf cichlid native to the Guaporé and Paraguay river basins in South America. They are renowned for their striking metallic blue sheen and the male's spectacular sail-like dorsal fin. As peaceful micropredators, they are excellent for planted community tanks, but require soft, acidic water, stable parameters, and a fine sand substrate to sift through.
Green Terror
Andinoacara rivulatus
A large, incredibly colorful, and highly aggressive South American cichlid. Known for their striking metallic green/blue scales and vibrant orange or white tail margins. As their name suggests, they are highly territorial and require very careful tankmate selection, usually only coexisting with other large, robust cichlids or armored catfish in very large tanks.
Chocolate Cichlid
Hypselecara temporalis
A large, deep-bodied South American cichlid famous for its 'gentle giant' temperament. They undergo significant color changes as they mature, eventually displaying rich chocolate browns, greens, and vibrant reds. Though peaceful for their size, they are still cichlids and will consume any fish small enough to fit in their mouths.