Care guide · Freshwater · fish

Neon tetra

Paracheirodon innesi

Photo: André Karwath aka Aka · Source · CC BY-SA 2.5Resized and compressed; no cropping or colour changes.

The neon tetra (Paracheirodon innesi) is a small, peaceful freshwater fish from the Amazon basin in Peru, Colombia and Brazil. Its luminous blue stripe and red rear half make it easy to recognise, even against dense planting. Unlike the cardinal tetra, the red does not extend along the entire belly. In an aquarium, neons spend much of their time in midwater, moving with their companions between open swimming space and cover. Watching that group behaviour is a large part of their appeal. They should therefore not be kept alone or added as a single splash of colour. Give the group a mature aquarium with sufficient length and planting that creates quiet, shaded areas. Successful care depends less on unusual equipment than on suitable water, stable conditions and tank mates that will not harass these small fish.

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At a glance

Temperature: 21–25 °C
pH: 6.0–7.0
GH: 1–8 °dGH
Aquarium length: At least 60 cm
Minimum aquarium volume: At least 54 L
Adult size: Approximately 3–4 cm
Group size: At least 8–10 individuals
Lifespan: 5–10 years
Swimming zone: Middle
Temperament: Peaceful
Lighting preference: Subdued lighting
Cover: Plants and sheltered areas
Staple food: Fine flakes, Small granules
Supplementary food: Live food, Frozen food, Finely crumbled dried natural food

54 L gross with a minimum 60 × 30 × 30 cm footprint and height is a lower limit for a neon tetra group, not a community stocking recommendation. Substrate and decor reduce actual water volume; tankmates require more space.

About this species

Adult neon tetras are approximately 3–4 cm long. The silvery belly and red band confined to the rear half distinguish them from cardinal tetras. When choosing fish, look beyond the blue stripe rather than assuming that both species have identical requirements.

Their colours may fade while resting and return after the lights come on. That change alone is not evidence of illness. Persistent fading accompanied by abnormal swimming, poor appetite or isolation does need attention. With good care, these fish can live for several years; LICG gives a lifespan of five to ten years.

Natural habitat

Neons originate from the upper Amazon basin, including small forest streams and tributaries rather than one single river habitat. They occur in both dark water coloured by organic matter and clear water.

Forest cover provides shade, roots, branches and fallen leaves, while the water is often soft and acidic. Not every natural site is densely planted: the surrounding forest also supplies shelter. In an aquarium, recreate that sense of cover and quieter spaces rather than concentrating solely on making the water brown.

Aquarium and layout

Choose a tank at least 60 cm long and leave usable swimming space. A tall tank of the same volume does not replace that length. A 60 × 30 × 30 cm aquarium has a calculated gross volume of 54 litres before substrate and furnishings; this is not a guarantee that any particular stocking plan will fit. A longer, larger aquarium offers more scope for a bigger group or additional inhabitants.

Plant the back and sides, using aquarium wood to create sheltered passages while leaving part of the centre open. A suitable dark substrate reduces reflections. Rocks are optional; if used, they should be stable, free of sharp edges and compatible with the intended water chemistry.

Create shaded patches with plants or floating cover. Provide filtration and gentle water movement without forcing the fish to swim constantly against a strong jet. Establish the aquarium and biological filter before adding the group.

Water conditions

This guide uses 21–25 °C, pH 6.0–7.0 and GH 1–8 °dGH as care guidance. These ranges are not an invitation to aim for their extremes. Test your source water and consider whether you can maintain stable conditions, including during water changes.

Reliable sources differ on the precise pH range. Here we follow LICG’s narrower recommendation and use Seriously Fish for temperature. The GH range is a conservative overlap between those two sources, not a proven biological optimum. Do not make abrupt pH changes simply to reach a number in a table.

Alongside pH and hardness, monitor ammonia/ammonium, nitrite and nitrate. Ammonium and nitrite should not be detectable in a properly functioning aquarium. Base water changes and maintenance on measurements and waste levels. Looking after the filter and avoiding excess food matter just as much as setting the heater.

Behaviour and group size

Keep neon tetras with their own species. For this example, we follow the advice to start with at least eight to ten individuals; ten is not an upper limit. A larger group is possible if the aquarium and overall stocking allow it. A shoal of another tetra species does not replace companions of their own kind.

Neons are generally peaceful. Potential tank mates should be calm, need compatible water conditions and be unable to regard them as prey. Avoid large predators, aggressive food competitors and fish that repeatedly chase the group. Compatibility involves more than a shared temperature: adult size, behaviour and available space all matter.

Feeding

Neons are small-mouthed omnivores. Their natural food includes small invertebrates and plant material, so aquarium feeding need not be limited to live or frozen foods.

Staple food

A complete dry food in fine flakes or small granules can form the basis of the diet. Check its intended use and, above all, whether the fish can actually swallow it. “Granules” describes a form, not a suitable particle size. Large pieces that are repeatedly spat out are a poor choice.

Supplementary food

Provide variety with appropriately small live or frozen foods, such as Daphnia or brine shrimp. Thaw frozen food and use a trustworthy supplier. Supplementary foods add variety to a balanced diet; they do not automatically replace a complete staple food.

For healthy adults, one or two small feeds a day are a useful general starting point. Offer roughly what the group eats within one to two minutes, then adjust to the fish in front of you. Check that every fish gets access and remove leftovers. Fry need much smaller food and a different feeding schedule.

Breeding

Spawning may occur in an aquarium, but raising fry deliberately needs separate preparation. Neons scatter eggs among fine material or plants and provide no parental care. Adults may eat the eggs, so a dedicated breeding tank with suitable egg protection makes management easier.

The eggs need low light and soft, acidic water. The sources give different precise breeding conditions, so this guide does not present one temperature recipe as a universal rule. Prepare the breeding tank, water monitoring and a dependable supply of very small first food before attempting to breed them. Newly hatched fry cannot eat the same food as adults. Planning to raise the young is therefore just as important as encouraging spawning.