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Serpae Tetra (Red Minor Tetra)

Hyphessobrycon eques

The Serpae Tetra or Red Minor Tetra (*Hyphessobrycon eques*) is an extraordinarily robust Characin with an incendiary color, characterized by a deep blood-red livery with a conspicuous comma-shaped (or rhombus-shaped) black spot just behind the gill cover. The fins, dark and bordered with a blinding white, are often held rigidly open in ritual threat poses, making the school constantly on display. Reaching 4 cm (1.5 inches) and possessing a very tall and compressed silhouette, it is a visually magnificent fish and almost indestructible in terms of water parameters. Nevertheless, it is notoriously famous in the aquarium hobby for being an unrepentant 'fin-nipper': if kept incorrectly, it will destroy the fins of any other slow or veiled tank mate.

Taxonomy
Class:Actinopteri
Order:Characiformes
Family:Characidae
Genus:Hyphessobrycon
Species:Hyphessobrycon eques

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Water Temperature

22 - 28 °C

pH Value

5.5 - 7.5

Water type

Freshwater

Tank level

Bottom and middle

Adult size

4.5 cm

Minimum tank volume

>= 80 L

Minimum group

>= 10

GH

1 - 15 dGH

KH

1 - 7 dKH

TDS

25 - 295 ppm

Conductivity

39 - 461 uS/cm

Species description

Geographical Origin and Habitat: Closely related to the Amazon Basin (Mato Grosso, Guapore, Paraguay). Lives among the thick grasses and marginal roots of slow-flowing rivers (Igarapés).
Taxonomy and Morphology: Serpae Tetra (Hyphessobrycon eques). Confused and historically sold as H. callistus or H. serpae. Massive rhomboidal shape (Rosy Tetra clade), but of a much more robust and predatory nature.
Social Behavior: The "Miniature Piranha" (Fin Nipper). A school (minimum 10 or 12) will create a fierce hierarchy system. Extremely bellicose towards other fish if the school is less than 6 individuals (they bite and tear fins).
Coloration and Sexual Dimorphism: Very dark blood red/brick red color all over the body. Shoulder marked by the classic lozenge-shaped black symbol. Anal fin almost black, dorsal fin black bordered with pure white. Vibrant scarlet male.

Care, breeding and tankmates

Aquarium Setup: They need a forest (100 cm+ / 40+ inches): bushes of stem plants (Hygrophila) and large intertwined woods that break their lines of sight, or the weakest will be hunted and bullied to death.
Diet and Feeding: Omnivore with a voracious bite. When bloodworms enter the water, the Serpae Tetra school stages a crazy "Feeding frenzy" tearing the frozen cube to pieces en masse.
Water Quality: Armored like a tank. Accepts the hardness of European tap water and huge pH variants (5-8), although in neutral/basic waters the colors regress from red to washed-out hazelnut.
Compatibility and Cohabitation: TERRIBLE companion for slow or veil-finned fish. Absolutely NEVER pair it with Guppies, Bettas, and even adult Angelfish will end up with chewed filaments. Excellent with large armored Cichlids, Loricariids and large Barbs.
Aquarium Breeding: Productive. They scatter adhesive eggs among Cabomba leaves, fertilized in groups (Egg-scatterer). They voraciously cannibalize both eggs and fry a millisecond after spawning.
Risks and Diseases: Community massacres. The shopkeeper will sell them to you as peaceful "Colorful Tetras": putting them in a standard 60-liter (15-gallon) tank with Guppies will lead to the systematic killing of the latter.

Geographic Origin and Distribution

Closely related to the Amazon Basin (Mato Grosso, Guapore, Paraguay). Lives among the thick grasses and marginal roots of slow-flowing rivers (Igarapés).

Origin

Amazon, Orinoco, and GuianasEurope, Mediterranean, and West Asia

Fish profile

Temperament
Active
This species has a lively and sometimes semi-aggressive temperament, especially if kept in too small of a group. They establish a pecking order within their school through frequent chasing and minor squabbles. Providing a large group and plenty of space minimizes their nipping tendencies towards other species.
Diet
Omnivore
This species is an opportunistic omnivore that will easily accept a wide variety of aquarium foods. A staple diet of high-quality flakes or pellets should be provided daily. For optimal health and coloration, supplement with frozen or live foods such as bloodworms and brine shrimp.
Sex ratio
School
Maintaining a proper sex ratio is less critical for this species compared to some others, as they are a schooling fish. Keeping them in groups of at least eight to ten individuals ensures natural behavior and reduces stress. Having a mix of males and females can help diffuse any minor squabbles among displaying males.
Feeding frequency
Twice daily
These active fish benefit from multiple small feedings throughout the day rather than one large meal. Feeding them two to three times daily with amounts they can consume in under two minutes is ideal. This schedule helps prevent bloating and keeps water parameters stable by reducing uneaten food.
Bioload
Low to Medium
As a moderately sized fish, this species produces an average bioload in the aquarium. Proper filtration is necessary to process the waste it generates efficiently. Routine maintenance and regular water changes will ensure a healthy environment.
Flow
Moderate
Originating from slow-moving tributaries and forested pools, they prefer gentle to moderate water currents. High flow environments can quickly exhaust these fish and cause them significant stress. A sponge filter or a baffled hang-on-back filter provides the perfect amount of water movement.
Jump risk
No
Reproduction
Oviparous
They are egg scatterers that do not provide any parental care to their offspring after spawning. To encourage breeding, a separate tank with soft, slightly acidic water and fine-leaved plants is required. Once eggs are laid and fertilized, the adult fish must be removed promptly to prevent them from eating the eggs.
Compatibility & tankmates
Aggressive
This species can be somewhat boisterous and has a tendency to nip the fins of slow-moving or long-finned tank mates. Keeping them in a sufficiently large school can help direct this behavior toward each other rather than other species. Care should be taken when selecting tank mates for this fish.
Tank level
Middle/Bottom
This species primarily occupies the middle region of the aquarium water column during normal activities. They are active swimmers that appreciate ample open swimming space in the center of the tank. They will frequently dart in and out of plant thickets or hardscape for cover when resting.

Window to the official scientific data of the species

Data synced on: 06/15/2026

Scientific Parameters & Models

Trophic level
3.1 ± 0.38 se
Resilience
High (less than 15 months)
Phylogenetic uniqueness (PD50)
0.5002
Bayesian Length-Weight
a = 0.01349, b = 3.14
VulnerabilityLow vulnerability (10 / 100)

Image gallery

Licensed images linked to the species or, when marked, to the closest representative taxon.

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Last updated: 06/30/2026
Serpae Tetra (Red Minor Tetra) (Hyphessobrycon eques) Care Guide & Tank Setup | Atlarium