Neon Tetra

About the species

The neon tetra (Paracheirodon innesi) is a tiny shoaling fish from the Solimões River basin in the Amazon, recognisable by the glowing blue-red stripe that stands out even in the shaded, tannin-stained waters of its natural habitat. Unlike the guppy, which tolerates a wide range of water hardness, the neon tetra comes from soft, acidic "blackwater" and is more sensitive to fluctuations in water quality, The species was scientifically described in 1936, and its popularity in the hobby grew quickly, helped along by the American aquarist William T. Innes, after whom it is named.so it is best added only to a well-established, mature tank.

Why it needs a shoal

The neon tetra is a strongly shoaling species and looks nervous in too small a group, with weaker colour because it spends most of its time hiding. At least 8–10 individuals is recommended, since in a larger shoal neon tetras swim more confidently throughout the tank and show their full colour. Fewer than 6 increases stress and affects the health of the whole group over time.

Aquarium: size and setup

A tank base of roughly 60 × 30cm, around 54 litres, is enough for a shoal of 8–10 neon tetras, though a densely planted, darker tank with a soft substrate better mimics their natural habitat and makes their colour stand out more. Gentle, not overly strong filtration matters, since neon tetras live in slow-moving or still water in the wild.

Water: soft and slightly acidic

The neon tetra comes from very soft water, with general hardness typically between 1 and 12 °dH and a pH between 5.0 and 7.0, clearly different from the guppy's need for hard, alkaline water. Temperature should be between 20 and 26°C – so the neon tetra does not need water as warm as the angelfish, which comes from warmer parts of the Amazon.

When to add neon tetras to a tank

Neon tetras are considered more sensitive to so-called new tank syndrome than many other beginner-friendly species, so it is best to add them only once the tank's nitrogen cycle is established and ammonia and nitrite readings are stably at zero. Buying neon tetras as the first fish in a brand-new tank is a common cause of early deaths.

Tankmates

The neon tetra is a peaceful species suited to a community tank with other small, calm fish of similar size, such as other tetras, rasboras or corydoras catfish. Larger or predatory species, such as an adult angelfish, may treat a small neon tetra as food, so that combination is not recommended except in very large, experienced setups.

Diet

The neon tetra is omnivorous and in the aquarium accepts small flakes and pellets, supplemented with frozen or live food such as mosquito larvae and daphnia. Because of its small mouth it needs appropriately sized food; oversized pieces are often left untouched, which can worsen water quality.

Similar species

The neon tetra is often confused with the related cardinal tetra (Paracheirodon axelrodi), whose red colouring runs the full length of the body rather than just the lower half as in the neon tetra, and with the green neon tetra (Paracheirodon simulans), which is smaller still. The distinction matters because these related species have somewhat different temperature and shoal-size requirements, so mixing them as one single group is not recommended.

Health risks

The neon tetra is known for so-called neon tetra disease (Pleistophora hyphessobryconis), an incurable parasitic disease that causes colour loss and body deformity, which is why quarantining new fish before adding them to an established tank makes sense. Spotting symptoms early allows the affected fish to be isolated and prevents spread to the rest of the shoal.

Pros & cons