Paracheirodon simulans (Blue Neon Tetra)

08 June 2026

493

Originating from the blackwater streams of the Orinoco and Negro rivers, the Blue Neon Tetra is a captivating schooling fish. Highly popular among aquascapers, its brilliant, continuous blue-green iridescent stripe pops beautifully in planted nano tanks. They are peaceful, active, and bring a stunning splash of color to soft-water aquariums.

Paracheirodon simulans (Blue Neon Tetra)

Overview

The Blue Neon Tetra (Paracheirodon simulans), frequently referred to in the hobby as the Green Neon Tetra, is a spectacular micro-fish beloved by aquarists. Though slightly smaller and more sensitive than the standard Neon Tetra, its vibrant, full-length iridescent stripe makes it a highly sought-after species for planted nano aquariums and biotope setups.

Image of blue neon paracheirodon simulans

Distribution and Habitat

This species is native to the upper Rio Negro and Rio Orinoco basins in South America. They naturally inhabit sluggish, highly acidic blackwater tributaries that are deeply stained with tannins from decaying leaves, branches, and organic matter. These waters are typically very soft and warm, shaded by dense rainforest canopies.

Description of Blue Neon Tetra

Body shape:

They possess a slender, elongated, and laterally compressed body that is perfectly adapted for darting through dense aquatic vegetation.

Color:

Their defining feature is a brilliant, continuous iridescent stripe that shifts between neon blue and green depending on the lighting. Unlike the common Neon Tetra, this stripe extends all the way from the nose to the base of the tail. The red coloration on their lower half is very faint or entirely absent, while the belly is a silvery-white.

Barbels:

They do not have barbels.

Snout:

The snout is short and relatively blunt, featuring a small terminal mouth designed for capturing tiny prey.

Eyes:

The eyes are large in proportion to their body, featuring a bright, reflective blue patch on the upper iris.

Fins:

All of their fins (dorsal, anal, pelvic, and pectoral) are mostly transparent and colorless.

The Tail:

The caudal fin is distinctly forked and completely transparent, aiding in their quick, agile movements.

Temper

They are exceptionally peaceful, docile, and somewhat timid fish. They do not bother other tank mates and are easily intimidated by larger or boisterous species.

Sociality

Blue Neon Tetras are highly gregarious schooling fish. To feel secure and display their best colors and natural behaviors, they must be kept in groups of at least 8 to 10 individuals. Larger schools of 20 or more create a breathtaking visual display.

Activity

They are mid-level swimmers that remain highly active during the day. You will often see them darting around the tank in tight, coordinated schools, especially when exploring open swimming spaces.

Keeping and Caring for Blue Neon Tetra

Tank size:

A minimum of 10 gallons (about 40 liters) is required for a small school, though larger tanks are always better to maintain stable water parameters.

Water Parameters:

Temperature

They prefer distinctly warmer water than standard neons, thriving between 24-30°C (75-86°F).

pH

They require highly acidic water to truly thrive, with an ideal pH range of 5.0 to 6.5.

Hardness

Water should be very soft, ideally between 1 and 5 dGH.

Ammonia, Nitrite, Nitrate

Ammonia and Nitrite must always be at 0 ppm. Nitrates should be kept strictly below 20 ppm through regular water changes, as they are sensitive to poor water quality.

Lighting

Dim to moderate lighting is preferred. Floating plants are highly recommended to diffuse bright aquarium lights and mimic their shaded natural habitat.

Water flow

They appreciate a gentle to sluggish water flow. Harsh currents will stress these small fish.

Decorations and Plants

A densely planted tank with driftwood, dark substrate, and leaf litter (such as Indian Almond leaves) is ideal. The tannins released by botanical materials will help lower the pH and bring out their most vibrant colors.

Diet

In the wild, they are omnivorous micro-predators feeding on tiny invertebrates. In the aquarium, they will readily accept high-quality crushed flakes, micro-pellets, and small live or frozen foods such as baby brine shrimp, daphnia, and cyclops.

Some Feeding Tips

Feed them small amounts 1 to 2 times daily. Because they have very small mouths, ensure that any dry food is crushed finely enough for them to easily consume.

Breeding

Breeding the Blue Neon Tetra in captivity is considered difficult due to their strict water parameter requirements. They are egg-scatterers that need extremely soft, highly acidic water (pH 5.0-5.5) and very dim lighting to trigger spawning. A separate breeding tank is necessary, and parents must be removed immediately after spawning to prevent them from eating the eggs. The fry are microscopic and require infusoria as their first food.

Conclusion

The Blue Neon Tetra is a dazzling and rewarding addition to a peaceful, soft-water aquarium. While they demand slightly stricter water parameters and warmer temperatures than other beginner tetras, their brilliant, glowing schooling behavior in a blackwater or heavily planted setup makes them one of the most beautiful micro-fish in the aquarium hobby.

Fish info

Care level: Moderate
Temperament: Peaceful
Adult size: 2-2.5 cm
Life expectancy: 3-5 years
Fish type: Tetra
Temperature : 24-30°C
pH: 5.0-6.5
Color Form: Blue, Green, Silver

Related on Fishs

Leave your comments

Latest on Fishs

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.
Leopard Angelfish (Pterophyllum scalare)

Moderate

South American freshwater cichlid

The leopard angelfish is a domestic color form of Pterophyllum scalare, a tall-bodied freshwater cichlid from tropical South America. Its silver to yellowish body is marked with irregular dark spots or broken vertical bars, although pattern intensity varies with age, mood and breeding line. It is generally peaceful in a suitably spacious community aquarium, but pairs become territorial when spawning. This fish needs warm, clean water, generous vertical swimming space and tank mates too large to swallow.
Yellow Labidochromis (Labidochromis caeruleus)

Easy - Moderate

Lake Malawi mbuna cichlid

The Yellow Labidochromis is a bright yellow mbuna cichlid from Lake Malawi. Labidochromis caeruleus is generally manageable for an African cichlid, but it remains territorial and needs hard, alkaline water, rockwork, and carefully chosen companions. The supplied source identifies two fish as a pair; sex and pair bonding cannot be confirmed from the available images. This species is an adaptable algae grazer, a maternal mouthbrooder, and a rewarding choice for an appropriately planned Malawi cichlid aquarium.
Blue Pearl Angelfish (Pterophyllum scalare)

Moderate

Freshwater cichlid

The Blue Pearl Angelfish is a selectively bred colour form of Pterophyllum scalare, the freshwater angelfish. Its laterally compressed body, extended fins and tall profile make it a striking inhabitant of a planted community aquarium. The supplied trade label supports identification as this species and colour form, although individual colour intensity can vary. It requires warm, stable, clean water, generous vertical swimming space and thoughtful tank-mate selection, especially as adults become territorial when pairing or spawning.
Villavicencio Dwarf Cichlid Apistogramma macmasteri

Moderate

South American dwarf cichlid

Apistogramma macmasteri, commonly called the Villavicencio dwarf cichlid, is a small South American cichlid associated with the Río Orinoco drainage of Colombia. It is valued for its compact size, elaborate finnage and interesting courtship behavior. A bonded pair can be kept in a carefully structured aquarium with soft, clean water, sand, cover and several potential spawning sites. Although manageable for an experienced community aquarist, territorial behavior increases during breeding, so tank layout and tankmate selection are important.
Neolamprologus leleupi (Tanganyika Golden Cichlid)

Moderate

Lake Tanganyika rock-dwelling cichlid

Neolamprologus leleupi is a small, brightly coloured cichlid endemic to Lake Tanganyika in East Africa. It inhabits rocky coastal areas and uses crevices for shelter, feeding and spawning. Despite its modest size, it can be strongly territorial, particularly when paired or breeding. The supplied source identifies these fish as a golden colour form and a pair, although sex cannot be confirmed reliably from the image alone. Successful care depends on alkaline, mineral-rich water, abundant rockwork and carefully chosen tank mates.
Maingano Cichlid (Melanochromis cyaneorhabdos)

Moderate - Difficult

Lake Malawi mbuna cichlid

The Maingano, or Johanni Maingano, is a Lake Malawi mbuna recognized for its intense steel-blue body and dark horizontal markings. The supplied label combines “Johanni” with the scientific name Melanochromis cyaneorhabdos; these are distinct species, so identification should be confirmed from the seller or locality. This territorial mouthbrooding cichlid needs hard, alkaline water, abundant rockwork, a predominantly algae-based diet, and careful stocking to limit aggression.
Red Chocolate Gourami (Sphaerichthys vaillanti)

Difficult

Blackwater labyrinth fish

The red chocolate gourami, Sphaerichthys vaillanti, is a specialized Southeast Asian labyrinth fish suited to mature, soft, acidic blackwater aquariums. It is peaceful but easily stressed by bright lighting, strong currents and boisterous tank mates. The supplied source identifies these fish as a pair; sex and exact identity cannot be confirmed from the image alone, so identification should be checked against a reliable specimen reference. Stable water quality, cover and a varied small-food diet are central to long-term success.
Pelvicachromis pulcher Purple Tilapia Pair Care Guide

Easy - Moderate

Small West African freshwater cichlid

Pelvicachromis pulcher, commonly called the kribensis or purple cichlid, is a small West African cave-spawning cichlid valued for its manageable size, attractive breeding colors and attentive parental behavior. A bonded pair can live in a community aquarium when provided with suitable cover and carefully chosen tank mates. The supplied listing identifies the fish as Pelvicachromis pulcher, although photographs alone cannot confirm the exact locality or color form.