Species · Aquatic pet

Neon Tetra

Paracheirodon innesi

Blackwater tetra from the upper Amazon whose electric stripe made it the emblem of the community aquarium.

The neon is the community tank’s jewellery: an electric blue-and-red stripe that only really works in numbers, where the shoal moves as one glittering object. Kept in the tens they are hardy, peaceful and mesmerising; kept in threes they are nervous and dull; kept with angelfish they are lunch. A settled, cycled, softish tank and a proper shoal is all the species asks — the classic beginner failure is adding these delicate-when-new fish to a tank that is itself only a week old.

At a glance

Lifespan: 4–8 years
Adult size: 3–4 cm
Minimum tank: 60 L for a shoal
Water: Tropical fresh, soft side, settled
Weekly upkeep: Weekly partial water change
Diet: Fine flake and micro pellets
Company: Ten or more; the shoal is the animal
With children: Watch, don’t touch
Tankmates: Small and peaceful only — no angels, no barbs

Varieties · 3 listed

The classic stripe is the fish; green and diamond variants exist, and the similar cardinal tetra wears its red full-length.

Classic
Diamond
Green

Right for you if

The tank has been running for months, not days — neons join established water.
Ten or more is the shopping list; the shoal is what you are buying.
Tankmates are small and calm, chosen with the neons in mind.
You want maximum visual return from a modest tank.

Wrong for you if

The tank was set up last weekend.
Angelfish or anything mouthy shares the water.
Three or four “to try” — that is a stressed huddle, not a shoal.
The heater is negotiable. It is not.

Welfare and sourcing — read this part

Ich — white spot — is a common protozoal infestation of home aquaria whose speed of reproduction is what makes it deadly,¹ and it announces itself exactly as named. Check every fish in the shop tank for white grains before buying from it, and quarantine the shoal before it meets your display.
Add neons to mature tanks only — most of what kills them in the first month is water, not disease.¹ A tank that has run happily for two months is the purchase trigger, not payday.
Buy the whole shoal from one healthy tank in one visit; a bag of ten settles together where drip-fed additions restart the stress each time.

Sources

Disorders and Diseases of Fish. MSD Veterinary Manual 2026. Accessed 2026-09-05. International MSD Veterinary Manual Many of the disorders and diseases that occur in fish are the result of stress, poor water quality, overcrowding, and failure to quarantine. New tank syndrome is ammonia accumulating when fish are added before the biological filter works, typically in the first one to three weeks. Ich (white spot) is a common protozoal infestation whose fast reproduction is what makes it deadly.

Every source here was checked, not recalled. Where this page makes a health statement and no source appears against it, that is not an oversight we have hidden — it means the claim is not yet sourced, and the build reports how many are in that state.

Availability, registration and keeping requirements differ from place to place. Check the rules where you live before you commit to any animal — we describe animals, not law.