Amazon red-tail tetra
Aphyocharax dentatus
A larger, more assertive relative of the common bloodfin tetra, reaching about 7 cm and showing a semi-aggressive temperament that clearly distinguishes it from more docile characins. The silver body with a pinkish-orange sheen on the caudal fins makes it visually appealing in schools of 5 or more. A fast swimmer almost always in motion, it is often used as a dither fish for medium-sized, semi-aggressive South American cichlids. Not to be confused with smaller, peaceful relatives like A. rathbuni.
Température de l’eau
22 - 28 °C
Valeur du pH
6 - 7.5
Type d'eau
Eau douce
Niveau dans le bac
Surface et milieu
Taille adulte
7 cm
Volume minimal du bac
>= 110 L
Groupe minimal
>= 5
GH
5 - 15 dGH
KH
2 - 7 dKH
TDS
95 - 295 ppm
Conductivité
148 - 461 uS/cm
Description de l'espèce
Geographical Origin and Habitat: Rio Paraguay basin (Brazil, Paraguay). Inhabits moderate-flow streams, clear rivers and flooded zones with dense riparian vegetation, where it moves agilely in schools.
Taxonomy and Morphology: False Bloodfin Tetra (Aphyocharax dentatus). Often confused with A. anisitsi. Differs by a slightly larger size, a mouth equipped with tiny visible "teeth" (hence "dentatus") and a more silvery livery.
Social Behavior: Very active schooling fish. It is essential to keep it in groups of at least 8-10 specimens. If in small numbers, it becomes shy or exhibits "fin-nipping" behaviors towards other slow tankmates.
Coloration and Sexual Dimorphism: Elongated silvery body. The anal and caudal fins feature extensive deep blood-red spots. Adult females are noticeably stockier and swollen with eggs; males are slimmer and have tiny hooks on the anal fin.
Soins, reproduction et cohabitation
Aquarium Setup: 80 cm (32 inches) tank or larger, with ample free swimming space in the center and dense bushes of plants on the sides. A dark bottom and not too blinding lighting (or shielded by floating plants) are preferable.
Diet and Feeding: Omnivorous micro-predator. Readily consumes quality flakes, but to keep the bright red color of the fins lit it needs brine shrimp, bloodworms and daphnia (both live and frozen) administered regularly.
Water Quality: Very robust and tolerant towards chemical value fluctuations. However, it does not like an excessive accumulation of nitrates. Efficient filtration with a moderate water flow is ideal.
Compatibility and Cohabitation: Excellent for robust community aquariums. Coexists perfectly with Corydoras, Ancistrus and dwarf or peaceful Cichlids (e.g. Bolivian Ram). Avoid insertion with long-finned fish (e.g. male Guppies or Bettas).
Aquarium Breeding: They scatter eggs among fine-leaved plants. Breeders must be conditioned with live food and separated in a breeding tank set up with mops or moss, then removed immediately after spawning to prevent cannibalism.
Risks and Diseases: Resistant to most common diseases. The main risk comes from jumping out of the aquarium (uncovered tanks) or from lethal intra-specific aggression if kept in groups of only 2 or 3 individuals.
Origine et répartition géographiques
Rio Paraguay basin (Brazil, Paraguay). Inhabits moderate-flow streams, clear rivers and flooded zones with dense riparian vegetation, where it moves agilely in schools.
Origine
Amérique du Sud hors Amazonie
Profil de poisson
- Tempérament
- Semi-aggressive
- The temperament of Aphyocharax dentatus is semi-aggressive and highly active, making them quite different from typical peaceful tetras. They have a tendency to nip fins and can be aggressive, particularly toward slower or long-finned tankmates. To manage this behavior, they must be kept in a sizable group of their own kind, which keeps their focus on internal hierarchy rather than harassing other species. Providing plenty of hiding spots and visual barriers also helps reduce territorial stress.
- Régime alimentaire
- Omnivore
- Aphyocharax dentatus is an omnivore with strong carnivorous and occasionally piscivorous tendencies. In their natural habitat, they feed on small insects, aquatic larvae, zooplankton, and sometimes fry or smaller fish. In the aquarium, they should be offered a varied diet consisting of high-quality flakes, micro-pellets, and regular feedings of live or frozen foods such as brine shrimp, daphnia, and bloodworms. A protein-rich diet is essential to maintain their energy levels and intense coloration.
- Espérance de vie
- 5-10 years
- Taille adulte
- 7 cm
- Ratio des sexes
- Group
- For general aquarium stocking, Aphyocharax dentatus is best kept in a mixed school rather than a specific male-to-female ratio. A group of at least 6 to 8 individuals is strongly recommended to establish a natural social hierarchy and dilute any internal aggression. If breeding is the goal, pairing them in a 1:1 ratio or setting up a small group with a slightly higher ratio of females to males is ideal. A larger group ensures that subdominant fish are not singled out for bullying.
- Fréquence d'alimentation
- Twice daily
- To match their high metabolism and active lifestyle, Aphyocharax dentatus should be fed once or twice daily. Food should be offered in small amounts that they can completely consume within two to three minutes. Overfeeding must be avoided, as uneaten food will quickly decay and degrade the water quality. Providing a varied feeding schedule with alternating dry and frozen foods keeps them healthy and active.
- Charge biologique
- Low to Medium
- Aphyocharax dentatus has a low-medium biological load due to its relatively small size (5–7 cm) and active nature. However, because of their fast metabolism and semi-carnivorous feeding habits, they produce more waste than smaller, sedentary tetra species. A high-quality filtration system with moderate turnover and regular partial water changes is essential to maintain pristine water conditions. Keeping nitrate levels low is critical for their long-term health and vibrant coloration.
- Courant
- Strong
- Native to the flowing river basins of Paraguay and Paraná, Aphyocharax dentatus prefers moderate to strong water currents in the aquarium. A noticeable flow stimulates their natural swimming instincts and helps them burn off energy, resulting in healthier muscular development. The filtration output should be positioned to create structured currents while still leaving some calmer areas near plants where the fish can rest. Utilizing a spray bar or powerhead can effectively replicate their native riverine habitats.
- Risque de saut
- Yes
- Aphyocharax dentatus poses a significant jump risk due to its high activity level and skittish nature when startled. They are agile swimmers capable of launching themselves out of the water, especially during feeding times, tank maintenance, or social chasing. It is absolutely essential to secure the aquarium with a tightly fitting lid or cover slides to prevent escapes. Floating plants can also help diffuse light and reduce the likelihood of them jumping by providing natural cover.
- Reproduction
- Oviparous
- Aphyocharax dentatus is an egg-scattering species, and breeding them in captivity is considered moderately challenging. Successful spawning requires a dedicated breeding tank with soft, slightly acidic water, dense fine-leaved plants like Java moss, or a spawning grid to protect the eggs. The parent fish will readily eat their own eggs and must be removed immediately after spawning is complete. The eggs hatch within 24 to 36 hours, and the fry must be fed infusoria or freshly hatched brine shrimp once they become free-swimming.
- Compatibilité et compagnons
- Community
- Due to their fin-nipping habits and active nature, Aphyocharax dentatus is compatible only with robust, fast-moving tankmates of similar size. Ideal tankmates include active barbs, rasoras, robust tetras, and bottom-dwelling species like Corydoras or smaller catfish. They should never be housed with slow-swimming, long-finned, or delicate species such as Angelfish, Bettas, or Guppies, which would easily become targets for bullying. Keeping them in a large school is key to ensuring peaceful coexistence in a community tank.
- Niveau dans le bac
- Top/Middle
- This active species primarily occupies the middle and upper levels of the water column. They require plenty of open swimming space in these zones to satisfy their energetic behavior and schooling tendencies. Providing dense vegetation along the back and sides of the tank while leaving the top-middle area free of obstructions will make them feel secure while allowing room to swim. They rarely venture to the bottom of the tank, except occasionally to grab falling food.
Modèles et paramètres scientifiques
FishBase
Fenêtre sur les données scientifiques officielles de l’espèce
FishBase v25.04Données synchronisées le : 15/06/2026
- Niveau trophique
- 3,4 ± 0,4 se
- Singularité phylogénétique (PD50)
- 0.5005
- Relation bayésienne longueur-poids
- a = 0.01047, b = 3.04
- VulnérabilitéVulnérabilité faible (10 / 100)
Galerie d'images
Images sous licence liées à l'espèce ou, lorsqu'elles sont indiquées, au taxon représentatif le plus proche.
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