Lapis Tetra
Hyphessobrycon cyanotaenia
A small Amazonian characin featuring a brilliant metallic blue stripe and red highlights, perfect for densely planted community tanks. Its vivid colors pop under subdued lighting.
Water Temperature
24 - 28 °C
pH Value
4.5 - 6.8
Water type
Freshwater
Tank level
Middle
Adult size
4 cm
Minimum tank volume
>= 60 L
Minimum group
>= 8
GH
1 - 8 dGH
KH
0.5 - 4 dKH
TDS
20 - 160 ppm
Conductivity
31 - 250 uS/cm
Species description
Geographical Origin and Habitat: This species is native to South America, restricted to the Rio Tapajós basin in the Pará state of Brazil. It inhabits slow-moving forest streams, small tributaries, and flooded forest areas characterized by clear or blackwater with dense overhanging vegetation, submerged roots, and a thick layer of leaf litter.
Taxonomy and Morphology: Belonging to the family Characidae and the genus Hyphessobrycon. It features a fusiform and laterally compressed body shape, typical of small tetras. It possesses a distinct adipose fin. It reaches a maximum adult size of 3.5 to 4.5 centimeters, making it well-suited for moderate-sized aquariums.
Social Behavior: Peaceful and highly gregarious. It must be kept in schools of at least 8-10 individuals. Keeping them in a group is vital to reduce their natural shyness, and it encourages males to display their brightest colors as they perform harmless sparring displays to establish minor social hierarchies.
Coloration and Sexual Dimorphism: The defining feature is a brilliant, reflective lapis-blue horizontal stripe extending from behind the gill cover to the base of the tail fin. The dorsal, adiposed, and caudal fins exhibit vibrant reddish-orange highlights. Adult males are slimmer and showcase much more intense coloration than the fuller-bodied females.
Care, breeding and tankmates
Aquarium Setup: A tank of at least 15-20 gallons (approx. 60-80 liters) is required for a school. The setup should replicate an Amazonian blackwater stream, utilizing a dark sand substrate, tangled driftwood branches, and hardy plants that thrive in shade. Adding dried beech or oak leaves to the bottom will release beneficial tannins.
Diet and Feeding: Omnivorous with a preference for small invertebrates. In captivity, they accept high-quality micro-pellets and flakes enriched with color-enhancing ingredients. Provide regular feedings of live or frozen foods, such as baby brine shrimp, daphnia, and cyclops, to maintain their health and vitality.
Water Quality: Requires soft (dH 1-8) and acidic water conditions, with pH kept between 5.5 and 6.5. Maintain temperatures between 23 and 27°C. Filtration should be efficient but gentle, avoiding strong currents. Peat filtration is highly beneficial for mimicking their natural water chemistry.
Compatibility and Cohabitation: Excellent choice for a peaceful community aquarium. They coexist well with other small tetras, dwarf cichlids (such as Apistogramma), Corydoras catfish, and small suckermouth catfish. Avoid placing them with large or aggressive species that might view these small tetras as food.
Aquarium Breeding: Breeding is challenging but achievable. It requires a separate breeding tank with very soft, highly acidic water (pH 5.0-5.5) and spawning mops or fine-leaved plants like Java moss. Parents do not guard the spawn and must be removed immediately after egg-scattering to prevent them from eating the eggs.
Risks and Diseases: Sensitive to sudden changes in water parameters. They are prone to Ich (white spot disease) if subjected to temperature fluctuations or transport stress. Maintaining pristine water conditions via regular, small water changes is key to preventing stress and disease outbreaks.
Geographic Origin and Distribution
This species is native to South America, restricted to the Rio Tapajós basin in the Pará state of Brazil. It inhabits slow-moving forest streams, small tributaries, and flooded forest areas characterized by clear or blackwater with dense overhanging vegetation, submerged roots, and a thick layer of leaf litter.
Origin
Amazon, Orinoco, and Guianas
Fish profile
- Temperament
- Peaceful
- The temperament of Hyphessobrycon cyanotaenia is overwhelmingly peaceful, making them an exemplary model of a docile community fish. They are not prone to fin-nipping or aggressive territorial disputes, provided they are kept in appropriately sized schools that allow them to establish a natural hierarchy. While males may occasionally engage in harmless sparring displays to establish dominance or impress females, actual physical damage is exceedingly rare. Their gentle nature ensures they will not harass slower-moving tank mates, fostering a tranquil and harmonious aquatic environment.
- Diet
- Omnivore
- In their natural habitat, Hyphessobrycon cyanotaenia are micro-predators and foragers that feed on tiny insects, crustaceans, and various zooplankton. Within the aquarium environment, they readily accept high-quality dry foods such as micro pellets and crushed flakes designed for small tropical fish. To ensure their best coloration and overall health, their diet should be regularly supplemented with live or frozen foods like Daphnia, newly hatched brine shrimp, and bloodworms. A varied diet prevents nutritional deficiencies and mimics their diverse natural foraging behavior.
- Life expectancy
- 3-5 years
- The beautiful Lapis Tetra has an average lifespan ranging between 3 and 5 years if housed under optimal conditions. It is a species particularly sensitive to nitrate accumulation and water parameter fluctuations, thus requiring regular water changes and excellent biological filtration. To bring out its splendid metallic blue coloration and ensure its longevity, the aquarium should feature a dark substrate, dense plants, and not excessively intense light. The school must consist of at least 8-10 specimens. The supply of high-quality live or frozen food is essential to satisfy its nutritional requirements.
- Adult size
- 4 cm
- The catalog's scalar value is 4 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 3.66 cm for this species, recorded as standard length (SL). The taxonomic record consulted is Hyphessobrycon cyanotaenia (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- Solitary
- While Hyphessobrycon cyanotaenia does not strictly require a specific male-to-female ratio, keeping a mixed group with a slight majority of females is generally recommended. Having more females helps distribute any amorous or territorial chasing behavior from the males, preventing individual females from becoming overly stressed. In larger schools of ten or more, the sex ratio becomes less critical as aggression and attention are widely dispersed throughout the group. Observing a healthy mix of both sexes also allows aquarists to enjoy the more intense, vibrant coloration that males display when showing off to the females.
- Feeding frequency
- Twice daily
- To maintain optimal health and vitality, Hyphessobrycon cyanotaenia should ideally be fed small portions one to two times per day. It is important to only offer an amount of food that the entire school can completely consume within two to three minutes. Overfeeding can lead to poor water quality, algae outbreaks, and potential health issues for these small fish. Providing a fasting day once a week can also be beneficial to clear their digestive tracts and replicate natural food scarcity.
- Bioload
- The bioload produced by Hyphessobrycon cyanotaenia is generally considered to be quite low due to their small adult size and active metabolism. These tiny fish do not generate significant amounts of waste, making them excellent candidates for densely planted setups or nano aquariums when kept in appropriate numbers. However, a proper filtration system and regular water changes are still essential to maintain optimal water quality. If kept in very large schools, their cumulative bioload can increase slightly, but it rarely overwhelms a standard, cycled aquarium filter.
- Flow
- Strong
- Coming from environments ranging from sluggish tributaries to moderately flowing streams, Hyphessobrycon cyanotaenia appreciates a gentle to moderate water flow in the aquarium. They are not built to constantly battle strong, torrential currents, which would quickly exhaust them and induce significant stress. Employing a spray bar or directing the filter outflow towards the tank glass can help diffuse the water movement effectively. Providing calmer resting areas among dense vegetation allows them to retreat and conserve energy whenever needed.
- Jump risk
- Yes
- Like many small, active species, Hyphessobrycon cyanotaenia possesses a moderate risk of jumping out of the aquarium, especially when startled or during the initial acclimation period. Sudden changes in lighting, aggressive tank mates, or sudden movements outside the tank can easily spook them into a leaping reflex. It is highly recommended to keep the aquarium securely covered with a tight-fitting lid or a specialized mesh screen. Floating plants can also be added to the surface to help them feel more secure and deter jumping behaviors.
- Reproduction
- Oviparous
- Hyphessobrycon cyanotaenia belongs to the category of egg-scattering fish, meaning they broadcast their eggs freely without providing any subsequent parental care. In a dedicated breeding setup, dim lighting, very soft, acidic water, and an abundance of fine-leaved plants or spawning mops are required to encourage spawning. The adult fish are notorious egg-eaters and must be removed from the breeding tank immediately after the spawning event concludes. Once hatched, the microscopic fry require infusoria or specialized liquid fry food until they are large enough to accept baby brine shrimp.
- Compatibility & tankmates
- Peaceful
- Hyphessobrycon cyanotaenia is an incredibly peaceful and sociable schooling fish that makes a fantastic addition to most community aquariums. They thrive when kept alongside similarly sized, non-aggressive species such as Corydoras catfish, small rasboras, and other docile tetras. It is crucial to avoid housing them with large or predatory fish that might view them as a quick snack, such as larger cichlids. Maintaining them in a group of at least six individuals will help them feel secure, significantly reducing any potential stress or shyness.
- Tank level
- Middle
- In the aquarium, Hyphessobrycon cyanotaenia primarily inhabits the middle to upper levels of the water column, rarely venturing completely to the bottom unless searching for fallen food. They are enthusiastic swimmers that appreciate plenty of open swimming space in the center of the tank to dart around in their schooling formations. Providing tall background plants or floating vegetation will give them the upper-level cover they desire without encroaching on their preferred swimming zones. Their mid-water presence makes them an excellent choice for adding active, colorful movement to the central focal point of a planted setup.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 2.9 ± 0.3 se
- Resilience
- High (less than 15 months)
- Phylogenetic uniqueness (PD50)
- 0.5
- Bayesian Length-Weight
- a = 0.01202, b = 3.09
- VulnerabilityLow vulnerability (10 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
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