Werner's Tetra
Hyphessobrycon werneri
A small, elegant freshwater tetra native to the Amazon basin, recognized by its long flag-like fins and peaceful schooling nature. It thrives in soft, slightly acidic waters.
Water Temperature
22 - 27 °C
pH Value
5.5 - 7
Water type
Freshwater
Tank level
Bottom and middle
Adult size
3.5 cm
Minimum tank volume
>= 60 L
Minimum group
>= 8
GH
2 - 10 dGH
KH
1 - 6 dKH
TDS
40 - 210 ppm
Conductivity
63 - 328 uS/cm
Species description
Geographical Origin and Habitat: Hyphessobrycon werneri is native to South America, specifically found in the lower Amazon River basin, coastal river systems of northern Brazil, and parts of Guyana. It inhabits slow-moving creeks, shallow forest streams, flooded plains, and lagoons where the water is calm, shaded by dense canopy, and rich in leaf litter.
Taxonomy and Morphology: Belonging to the family Characidae and genus Hyphessobrycon, this species is a typical small characin. It features a slender, laterally compressed body shape. Mature males are morphologically unique due to the extreme elongation of the soft rays in both the dorsal and anal fins, resembling delicate sails.
Social Behavior: It is a strictly schooling species that must be kept in groups of 6 to 8 individuals or more. They form cohesive groups that swim in the mid-water layers. Males display to one another by flaring their dramatic fins in a harmless display of dominance and courtship, creating a fascinating visual spectacle. They are peaceful.
Coloration and Sexual Dimorphism: The body has a semi-translucent yellowish-grey base with iridescent silver, blue, or green scales along the lateral line. The fins are reddish to blackish toward the tips. Sexual dimorphism is highly apparent: males have significantly longer dorsal and anal fins, brighter coloration, and are slightly larger than females.
Care, breeding and tankmates
Aquarium Setup: A tank of at least 15-20 gallons (60-80 liters) is required for a small school. The aquarium should be densely planted with species like Cryptocoryne, Java fern, and floating plants to dim the light. Use a dark sandy substrate, driftwood branches, and dry leaves to mimic a blackwater environment, leaving space for swimming.
Diet and Feeding: They are omnivorous micropredators. In captivity, they should be fed a varied diet consisting of high-quality micro-granules or flakes, supplemented regularly with live or frozen foods such as baby brine shrimp, daphnia, cyclops, and finely chopped bloodworms. Feeding small portions twice daily is recommended.
Water Quality: Requires soft, acidic water conditions. Keep the water temperature between 73-81 °F (23-27 °C). The pH should be maintained between 6.0 and 7.0, with GH below 8 and KH below 4. Regular small water changes (10-15% weekly) are essential, as this species is sensitive to accumulated organic waste and high nitrate levels.
Compatibility and Cohabitation: Excellent tankmate for peaceful community tanks. Ideal companions include other small tetras, pencilfish, corydoras catfish, otocinclus, and dwarf cichlids (such as Apistogramma). Avoid stocking them with large or highly active fish (like barbs or large cichlids) that may nip their long fins or consume them.
Aquarium Breeding: Breeding is possible but requires a separate spawning tank with very soft, acidic water (pH 5.5-6.0) and spawning mops or fine-leaved mosses. Elevate temperatures slightly. After spawning, the parent fish must be immediately removed to prevent egg predation. Feed the tiny fry with infusoria followed by rotifers.
Risks and Diseases: They are susceptible to ich (white spot disease) if sudden temperature drops occur. Their long, delicate fins can be damaged by coarse decorations or nipped by incompatible fish, leading to fin rot. They also tolerate poor water conditions poorly, showing rapid stress and loss of coloration.
Geographic Origin and Distribution
Hyphessobrycon werneri is native to South America, specifically found in the lower Amazon River basin, coastal river systems of northern Brazil, and parts of Guyana. It inhabits slow-moving creeks, shallow forest streams, flooded plains, and lagoons where the water is calm, shaded by dense canopy, and rich in leaf litter.
Origin
Tropical oceans and reefsAmazon, Orinoco, and Guianas
Fish profile
- Temperament
- Peaceful
- The temperament of Hyphessobrycon werneri 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 werneri 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 average life expectancy for this species in the aquarium ranges from 3 to 5 years. To help achieve this milestone, it is essential to recreate a quiet and sheltered environment, characterized by dense aquatic vegetation and a moderate water flow. Soft and acidic water (pH 5.5-6.5) is highly recommended to preserve the health of its immune system. Since it is a schooling fish, it must be kept in groups of at least 6-8 individuals; isolation causes severe stress that drastically reduces its life expectancy. The diet must include small live or frozen organisms such as cyclops and newly hatched brine shrimp.
- Adult size
- 3.5 cm
- The catalog's scalar value is 3.5 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 3.2 cm for this species, recorded as standard length (SL). The taxonomic record consulted is Hyphessobrycon werneri (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
- School
- While Hyphessobrycon werneri 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 werneri 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 werneri 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
- Stagnant
- Coming from environments ranging from sluggish tributaries to moderately flowing streams, Hyphessobrycon werneri 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 werneri 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 werneri 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
- Hyphessobrycon werneri 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/Bottom
- In the aquarium, Hyphessobrycon werneri 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 = 0.00676, b = 3.12
- VulnerabilityLow vulnerability (10 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
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