Hyphessobrycon hyanuary (Costello Tetra)

06 August 2026

329

The Costello Tetra, scientifically known as Hyphessobrycon hyanuary, is a peaceful and active schooling fish native to the Amazon basin. Known for its subtle greenish-gold lateral stripe and distinctive black tail spot, this hardy tetra is a popular and undemanding choice for community aquariums.

Hyphessobrycon hyanuary (Costello Tetra)

Overview

The Costello Tetra, also known as the January Tetra (derived from its species name hyanuary), is a delightful and hardy freshwater fish belonging to the family Characidae. While not as vibrantly colored as the traditional Neon Tetra, it boasts a subtle, elegant beauty with its olive-green to silvery body and a striking black patch at the base of the tail, topped by a luminous golden-green stripe. It is highly regarded by aquarists for its peaceful nature and ease of care, making it an excellent addition to beginner and advanced community tanks alike.

Image of gruener neon hyphessobrycon hyanuary

Distribution and Habitat

This species is endemic to South America, specifically found in the upper Amazon River basin in Brazil. It was originally discovered in Lake Hyanuary, a floodplain lake near Manaus, which gave the fish its scientific name. In its natural habitat, the Costello Tetra inhabits slow-moving, heavily vegetated tributaries, flooded forests, and blackwater environments rich in tannins from decaying plant matter.

Description of Costello Tetra

Body shape:

The Costello Tetra features a classic tetra profile—laterally compressed and somewhat deep-bodied, allowing it to navigate easily through dense aquatic vegetation.

Color:

The base coloration is typically a silvery-olive or translucent grey. Its most defining feature is a prominent black spot on the caudal peduncle (the base of the tail), which is immediately bordered above by a reflective, iridescent golden-green line.

Barbels:

Like other characins, this species does not possess barbels.

Snout:

It has a relatively short snout with a terminal mouth, perfectly adapted for snatching small food particles from the water column.

Eyes:

The eyes are comparatively large with a bright, often slightly golden or silvery iris, aiding their vision in dimly lit blackwater environments.

Fins:

The fins are mostly translucent, though the dorsal and anal fins can sometimes show a faint whitish tint at their very tips.

The Tail:

The caudal fin is deeply forked and clear, with the distinct black blotch from the body often extending slightly into the base of the upper and lower lobes.

Temper

This is an exceptionally peaceful species. They do not nip fins or bother tank mates, making them ideal residents for a mixed community aquarium containing other small, docile fish.

Sociality

Costello Tetras are highly social, schooling fish. They must be kept in groups of at least 6 to 8 individuals to feel secure, display their best colors, and exhibit natural schooling behaviors. When kept alone or in too small of a group, they can become highly stressed and withdrawn.

Activity

They are very active swimmers that primarily occupy the middle and upper levels of the aquarium. They are constantly on the move, darting playfully among plants and open swimming spaces.

Keeping and Caring for Costello Tetra

Tank size:

A minimum tank size of 60 liters (15 gallons) is recommended for a small school. A longer tank is preferable as it provides more horizontal swimming space.

Water Parameters:

Temperature

They thrive in tropical temperatures ranging from 22 to 26°C (72-79°F).

pH

The ideal pH range is slightly acidic to neutral, between 6.0 and 7.5.

Hardness

They prefer soft to moderately hard water, ideally between 2 and 15 dGH.

Ammonia, Nitrite, Nitrate

Ammonia and Nitrite must always be at 0 ppm. Nitrates should be kept as low as possible, ideally below 20 ppm, through regular water changes.

Lighting

Subdued or moderate lighting is best. Floating plants can be used to diffuse bright aquarium lights, which will help the fish feel more secure and encourage them to show their best colors.

Water flow

A gentle to moderate water flow mimics their natural slow-moving habitat. Harsh currents should be avoided.

Decorations and Plants

A heavily planted tank with dark substrate is ideal. Incorporate driftwood, dried Indian almond leaves (to add beneficial tannins), and plenty of background and midground plants, while leaving a clear open area in the center for swimming.

Diet

Costello Tetras are omnivorous and not fussy eaters. In the aquarium, they will readily accept high-quality crushed flake foods and micro-pellets. To ensure optimal health and coloration, supplement their diet with live or frozen foods such as daphnia, brine shrimp, and bloodworms.

Some Feeding Tips

Feed them small amounts 1 to 2 times a day, only providing what they can consume within 2-3 minutes. Because they have small mouths, ensure all food particles are appropriately sized.

Breeding

Breeding the Costello Tetra is relatively straightforward as they are egg-scatterers that exhibit no parental care. To breed them, set up a separate dimly lit breeding tank with soft, slightly acidic water and fine-leaved plants like Java Moss or spawning mops. Condition the breeding pair or group with high-quality live foods. Spawning usually occurs in the early morning. Once eggs are scattered, the adult fish must be removed immediately to prevent them from eating the eggs. The fry will hatch in about 24 to 36 hours and will need to be fed infusoria or specialized liquid fry food until they are large enough to accept newly hatched brine shrimp.

Conclusion

The Costello Tetra (Hyphessobrycon hyanuary) is a fantastic, low-maintenance species that brings lively movement and subtle elegance to any freshwater setup. Their peaceful temperament, hardiness, and engaging schooling behavior make them an excellent choice for both novice fishkeepers setting up their first community tank and experienced aquarists looking for a classic Amazonian biotope resident.

Fish info

Care level: Easy
Temperament: Peaceful
Adult size: 4 cm
Life expectancy: 3-5 years
Fish type: Tetra
Temperature : 22-26°C
pH: 6.0-7.5
Color Form: Black, Gold, Green, Silver

Related on Fishs

Leave your comments

Latest on Fishs

Dwarf Gourami Red (Trichogaster lalius)

Easy - Moderate

Asian labyrinth fish

The red dwarf gourami is a selectively bred color form of the dwarf gourami, a small labyrinth fish formerly widely known as Colisa lalia. It is suited to mature, planted community aquariums with gentle water movement and calm tank mates. Males can be territorial, especially when kept with females in confined conditions, so cover, visual barriers, and careful observation are important for a pair.
Cockatoo Cichlid Red (Apistogramma cacatuoides)

Moderate

South American dwarf cichlid

The Cockatoo Cichlid is a small South American dwarf cichlid valued for its personality, breeding behavior and colorful finnage. Apistogramma cacatuoides is generally adaptable when provided with clean, stable water, cover and a soft substrate. Males are larger and more vividly marked than females, while pairs become territorial around spawning sites. The supplied “red” designation most likely refers to a selectively bred color form; exact strain and sex confirmation cannot be established from the listing alone.
Discus (Symphysodon aequifasciatus) Care Guide

Difficult

South American freshwater cichlid

Symphysodon aequifasciatus is a large, laterally compressed cichlid from the Amazon Basin, valued for its calm behavior and striking disc-shaped body. It requires warm, clean, stable water and careful feeding, making it better suited to experienced aquarists. The supplied images show yellow, orange, red, white and dark color forms; cultivated strains can vary considerably, so exact variety identification from images alone is uncertain. Discus are social fish and generally thrive in groups rather than as isolated specimens.
Cape Lopez Killifish (Aphyosemion australe)

Moderate

West African non-annual killifish

The Cape Lopez killifish is a small, peaceful West African freshwater fish prized for its patterned body, flowing fins and manageable size. It inhabits slow-moving and temporary waters around coastal Gabon, including the Cape Lopez region. The supplied trade description identifies a pair as “Cape Lopez splendid carpets,” but this wording may describe a commercial strain rather than a formally recognized taxon. The image appears to show an orange form, so exact strain identification should be confirmed with the breeder or supplier.
Burton’s Mouthbrooder (Astatotilapia burtoni)

Moderate

East African haplochromine cichlid

Burton’s mouthbrooder, Astatotilapia burtoni, is a moderately aggressive East African haplochromine cichlid known for strong social hierarchies and maternal mouthbrooding. Males become more vividly patterned and defend territories, while females are generally less colorful and carry eggs and fry in the mouth. A pair requires a spacious, well-filtered aquarium with rocky cover, alkaline water and carefully selected tank mates. The supplied identification is consistent with Astatotilapia burtoni, although sex and locality form cannot be confirmed from the photographs alone.
Cyrtocara moorii (Blue Dolphin Cichlid) Care Guide

Moderate

Lake Malawi haplochromine cichlid

Cyrtocara moorii is a large, distinctive haplochromine cichlid from Lake Malawi, recognised for its blue adult coloration and rounded forehead, which becomes more pronounced with age. It is a maternal mouthbrooder and is generally less aggressive than many Malawi mbuna, but its size and territorial breeding behaviour require a spacious aquarium. The supplied images appear consistent with blue C. moorii, although photographs cannot confirm sex, locality, or whether the fish form a true bonded pair.
Blue Dwarf Gourami Pair (Trichogaster lalius)

Easy - Moderate

Peaceful labyrinth fish

The blue dwarf gourami is a selectively colored form of a small labyrinth fish native to the Indian subcontinent. It spends much of its time in the upper and middle aquarium, using its specialized labyrinth organ to breathe atmospheric air. Males can become territorial, especially when nesting, so a planted aquarium with calm tank mates, gentle flow, and surface cover is important. The supplied name uses Trichopodus lalius; Trichogaster lalius is the commonly used current combination.
Blue Acara (Aequidens pulcher)

Moderate

South American freshwater cichlid

The supplied label identifies these fish as Blue Acara, Aequidens pulcher, a South American freshwater cichlid often placed in the genus Andinoacara in current aquarium literature. The photograph is consistent with a blue acara, although a definitive identification cannot be confirmed from one image alone. This pair requires a spacious aquarium, stable water quality, hiding places and careful observation during breeding, when territorial behavior becomes stronger.
Julidochromis transcriptus: Black-and-White Slender Cichlid

Moderate

Lake Tanganyika rock-dwelling cichlid

Julidochromis transcriptus is a small rock-dwelling cichlid from Lake Tanganyika, recognized by its compact, elongated body and irregular black-and-white pattern. It is a territorial cave dweller that is best kept as an established pair in a carefully structured aquarium. The supplied fish are identified as a DNZ pair, although sex, collection locality, and precise geographic form cannot be verified from the supplied material alone.
Azur Cichlid (Sciaenochromis fryeri) Care Guide

Moderate

Lake Malawi haplochromine cichlid

The Azur cichlid is commonly sold as Sciaenochromis fryeri, a predatory haplochromine cichlid from Lake Malawi. Mature males develop vivid electric-blue coloration, while females and juveniles are generally less intensely colored. This fish is moderately aggressive and needs a spacious aquarium with rocky structure, alkaline, mineral-rich water, and carefully selected tank mates. The supplied source describes a DNZ pair, but sex and exact locality cannot be confirmed from the images alone. Identification confidence is therefore good but not absolute.
Marble Angelfish (Pterophyllum scalare)

Moderate

South American freshwater cichlid

The marble angelfish is a captive-bred color form of Pterophyllum scalare, a tall-bodied South American cichlid valued for its elegant fins and distinctive irregular black patterning. It needs a mature, spacious aquarium with excellent water quality, warm water and suitable tank mates. Although generally manageable, adults establish territories and may become assertive when pairing or spawning. The supplied source identifies two marble angelfish; exact lineage and strain details cannot be confirmed from the available information.
Gold Angelfish, Pterophyllum scalare

Moderate

Freshwater South American cichlid

The Gold Angelfish is an ornamental colour form of Pterophyllum scalare, a tall-bodied South American cichlid valued for its graceful movement and parental care. It needs a mature, spacious aquarium with substantial vertical clearance, stable warm water and carefully chosen tank mates. The supplied source identifies two fish as Gold Angelfish, although the accompanying images show several angelfish colour and fin forms, so the exact appearance of the supplied specimens cannot be confirmed from the images alone.
Zebra Angelfish (Pterophyllum scalare)

Moderate

South American freshwater cichlid

The Zebra Angelfish is a selectively bred form of Pterophyllum scalare, recognised by a silvery body with several dark vertical bars and the tall, laterally compressed shape typical of freshwater angelfish. The supplied images also show other angelfish colour forms, so the exact appearance of the listed pair cannot be confirmed from the image set alone. This South American cichlid is generally manageable for experienced community keepers, but its size, territorial breeding behaviour and need for a tall aquarium should be planned for carefully.
Black Angelfish (Pterophyllum scalare)

Moderate

South American freshwater cichlid

The supplied record identifies two black angelfish, most likely a domestic color form of Pterophyllum scalare. The photographs show several angelfish color patterns, so they should not be treated as proof that every pictured fish is black or that all belong to the same strain. Black angelfish retain the tall, laterally compressed body and extended fins typical of freshwater angelfish. They need a tall, mature aquarium, stable warm water, a varied diet, and carefully selected tank mates.
White Marble Angelfish (Pterophyllum scalare)

Moderate

Freshwater cichlid

The white marble angelfish is a selectively bred aquarium color form of Pterophyllum scalare, a tall-bodied South American cichlid valued for its elegant fins and distinctive irregular dark marbling. It is generally peaceful when young but can become territorial, especially when paired for spawning. Successful care depends on a tall aquarium, excellent water quality, suitable tank mates, and a varied carnivorous-omnivorous diet. The exact genetic strain shown cannot be confirmed from photographs alone.
Freshwater Angelfish Mix (Pterophyllum scalare)

Moderate

Freshwater cichlid

Freshwater angelfish are tall-bodied South American cichlids valued for their graceful movement and wide range of captive color forms. The supplied source identifies a mixed group as Pterophyllum scalare; the photographs show several forms, including striped, black, orange, white, silver and blue-toned fish. They are manageable for experienced beginners, but their adult height, territorial breeding behavior and tendency to eat small tank mates require thoughtful aquarium planning.