Blue emperor tetra
Inpaichthys kerri
An Amazonian tetra of regal beauty: the male displays an intense metallic blue with a blue adipose fin — a diagnostic detail distinguishing it from the female, who has the same fin in orange-red. Native to tributaries of Brazil's Rio Madeira basin. In schools of 8–10+ on dark substrate with dense plants and dim lighting, the males' blue reaches hypnotic depth. In groups that are too small it may develop fin-nipping tendencies. Breeding of intermediate difficulty.
Temperatura da água
24 - 27 °C
Valor de pH
5.5 - 7
Tipo de água
Água doce
Nível do tanque
Meio
Tamanho adulto
3,5 cm
Volume mínimo do tanque
>= 60 L
Grupo mínimo
>= 6
GH
1 - 12 dGH
KH
1 - 6 dKH
TDS
25 - 240 ppm
Condutividade
39 - 375 uS/cm
Descrição da espécie
Geographical Origin and Habitat: Rio Aripuanã Basin (Brazilian Amazon). Populates the slow-flowing inlets shaded by the dense rainforest, on bottoms of sand and fallen branches.
Taxonomy and Morphology: Blue Emperor Tetra (Inpaichthys kerri). The only member of its genus. Often confused with Nematobrycon palmeri, it is distinguished by the presence of the dorsal adipose fin (absent in palmeri).
Social Behavior: Very lively schooling fish and formidable swimmer. Males engage in continuous, harmless fights parrying with spread fins to dominate the attention of the females of the school.
Coloration and Sexual Dimorphism: Cobalt Blue. Males (more slender) show a bright bluish lateral band on a purplish/lavender background; females are stockier, yellowish-gray, with a black band. The blue lights up only in acidic water.
Cuidado, criação e companheiros de tanque
Aquarium Setup: 80 cm (32 inches) tank. Requires ample space for horizontal free swimming in the center and a dense barrier of plants on the sides. Submerged roots and dim light will make their otherwise dull livery explode.
Diet and Feeding: Voracious micropredator. Hunts insects in mid-water. Excellent eater of live daphnia, bloodworms and brine shrimp. Immediately accepts fine dry granules for characins.
Water Quality: Tolerates a medium GH, but to show the "Blue Emperor" reflection strictly requires a pH below 6.8 and water filtered with active granular peat.
Compatibility and Cohabitation: Excellent community fish. Unlike some nippy tetras, it ignores its companions (does not bite long fins). Ideal with Apistogramma, Corydoras and bottom Loricariids.
Aquarium Breeding: Egg scatterer. In the morning, the couple side by side releasing non-adhesive eggs in the moss (Taxiphyllum). Once the parents are removed (they would eat them), the eggs hatch in 24 hours.
Risks and Diseases: Visual Stress Pallor. If kept in bare tanks, too illuminated (without floaters) or on blinding white gravel, the fish deactivates the chromatophores, resulting in mouse gray for its entire life.
Origem e distribuição geográfica
Rio Aripuanã Basin (Brazilian Amazon). Populates the slow-flowing inlets shaded by the dense rainforest, on bottoms of sand and fallen branches.
Origem
Amazônia, Orinoco e Guianas
Perfil de peixe
- Temperamento
- Peaceful
- They are a peaceful, energetic schooling fish that must be kept in groups of eight or more. In proper numbers, they will interact actively with one another, establishing a fascinating pecking order. In numbers too small, they may nip fins out of stress.
- Dieta
- Omnivore
- They are unfussy omnivores that will readily accept a wide variety of foods. Offer a staple of high-quality flakes or micro-pellets. Supplement this regularly with live or frozen foods like daphnia, bloodworms, and brine shrimp.
- Expectativa de vida
- 3-6 years
- Tamanho adulto
- 3.5 cm
- Proporção sexual
- Group
- Males are noticeably more slender and display a much more intense, solid blue coloration. Females are plumper with a more subdued brownish-blue tint. Keeping them in a mixed group allows males to display their best colors while showing off.
- Frequência de alimentação
- Twice daily
- Feed them small pinches once or twice a day, ensuring all food is consumed within a few minutes. They are active feeders that primarily eat from the mid-water column. Avoid overfeeding to prevent compromising water parameters.
- Carga biológica
- Low
- As a small species, the Blue Tetra contributes a very low bioload to the aquarium system. Standard biological and mechanical filtration easily processes their waste. Regular partial water changes keep the water quality optimal for their vibrant colors.
- Fluxo
- Moderate
- They thrive in a moderate water flow that simulates the gentle currents of their natural forest streams. A well-placed filter outlet or small powerhead will encourage active swimming behaviors. Calm areas should also be available for resting.
- Risco de salto
- No
- Reprodução
- Oviparous
- They are egg scatterers that require a separate breeding tank with soft, acidic water and fine-leaved plants. The parents offer no care and will consume the eggs if given the chance. Remove the adults immediately after spawning is complete.
- Compatibilidade e companheiros de tanque
- Peaceful
- They are generally peaceful but can sometimes become slightly nippy if not kept in a large enough school. They do well with other similarly sized tetras, rasboras, and corydoras. Avoid keeping them with slow-moving fish possessing long, flowing fins.
- Nível do tanque
- Middle
- They are highly active swimmers that predominantly occupy the middle regions of the aquarium. The tank should provide extensive open swimming areas along the front and middle. Dense planting around the back and sides provides necessary cover.
Modelos e parâmetros científicos
FishBase
Acesso aos dados científicos oficiais da espécie
FishBase v25.04Dados sincronizados em: 15/06/2026
- Nível trófico
- 3,1 ± 0,4 se
- Resiliência
- Alta (menos de 15 meses)
- Unicidade filogenética (PD50)
- 0.5625
- Relação bayesiana comprimento-peso
- a = 0.01738, b = 3.05
- VulnerabilidadeVulnerabilidade baixa (10 / 100)
Galeria de imagens
Imagens licenciadas vinculadas à espécie ou, quando marcadas, ao táxon representativo mais próximo.
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