Photo: Holger Krisp · CC BY 3.0
Freshwater · Beginner · 10+ gal
Paracheirodon innesi
By Fishy Dave
Keep neon tetras in a school of at least 6, and plan on 8 to 12 in a 20-gallon tank. Adults stay under 1.5 inches. A 10-gallon is the minimum for a small school. Hold the water at 72 to 78°F, soft and slightly acidic (pH 5.5 to 7.0), with plants and dim light.
| Water type | Freshwater |
|---|---|
| Care level | Beginner |
| Minimum tank | 10 gallons |
| Temperament | Peaceful schooling fish. Keep in groups of six or more; tens are better. They are shy when kept in ones and twos. |
| Diet | Omnivore. Quality micro pellets or flakes, plus frozen or live baby brine shrimp, daphnia, and finely chopped bloodworms. Feed small amounts twice daily. |
| Temperature | 72–78 °F |
| pH | 5.5–7 |
| Hardness / salinity | Soft, slightly acidic water is ideal (around 1–10 dGH). They adapt to moderate hardness if changes are slow and the tank is stable. |
Paracheirodon innesi is a tight-schooling characin from blackwater-influenced streams. A pair in a bright, bare tank will hide and fade. Six is a minimum; eight to twelve in 20 gallons looks more natural and spreads stress.
They stay under about 1.5 inches. The limiting factor is group size and water quality, not the length of a single fish.
Ten gallons can house a small school if filtration and maintenance are solid. Twenty gallons is more forgiving and leaves room for corydoras or shrimp in a peaceful 20-gallon community.
They color up over a dark substrate, with plants, driftwood, and leaf litter or tannins. Bright, open water with nowhere to hide is a common reason neons 'never look like the picture.' A gentle sponge or hang-on-back filter is enough.
Neon tetras are sensitive to poor cycling, big parameter swings, and crowding. 'Neon tetra disease' (Pleistophora) shows as cysts, fading color, and restlessness. Unlike ich, it has no reliable home cure, so prevention is the plan: quarantine, quality sources, and clean water.
They prefer cooler tropical temperatures than discus or some bettas, so set an adjustable heater for the mid-70s °F. Do not keep them long-term at the hot end of the tropical range. Cardinal tetras look almost the same but run warmer. The neon tetra vs cardinal tetra guide shows how to tell them apart.
A few listings we would open for this species. Skip anything you already own that still works.
Hikari Tropical Micro Pellets, 0.77 oz
Neons have small mouths. These semi-floating micro pellets were made for tetras and other small schoolers, and they sink slowly enough that the whole group gets a shot.
Feed a pinch twice a day, not a pile. Skip this if you already use a quality micro pellet or crushed flake they finish in a minute. Frozen baby brine is still worth adding a few times a week.
See this listingAqueon Adjustable Pro heater, 100W
A school belongs in 10–20 gallons, and that volume still needs stable mid-70s F. Neons fade when the tank swings. Same 100W Pro we would open for a 20-gallon tropical kit.
Skip 100W in a true 10-gallon. The 50W Pro is enough there. Do not run them at the hot end of tropical just because a betta shares the stand.
See this listingFluval AquaClear 50 Power Filter
A 20-gallon school needs a hang-on-back you can stuff with extra sponge, not a sealed cartridge. Flow is adjustable, which matters for small tetras.
Dial it down and baffle the output if they huddle in the corner. Skip this on a 10-gallon if a sponge filter already keeps ammonia at zero. Confirm the 20-to-50 gallon size on the listing. Fluval still sells this as AquaClear 50.
See this listingAt least six, and more is better. A school of eight to twelve in a 20-gallon tank is a comfortable community starting point.
A 10-gallon tank can work for a small school. A 20-gallon is easier to keep stable and looks more natural.
Sometimes, in 10 gallons or larger, if the betta is not a hunter and the neons have cover. Watch the first days closely and have a backup plan.
Six. Fewer than that and they hide and lose color. Eight to twelve in a 20-gallon looks more natural and spreads stress.
10 gallons for a small school of six, if filtration and maintenance are solid. A 20-gallon long is more forgiving and fits 8 to 12 neons with a group of cories.
Adults stay under about 1.5 inches. Because each fish is so small, the school size and water quality decide the tank, not the length of one fish.
A cycled 10-gallon or larger, a school of at least six, 72 to 78°F, and soft, slightly acidic water (pH 5.5 to 7.0). Add a gentle filter, plants, a dark substrate, and dim light, and feed small amounts twice a day.
Next step
Plan on 10 gallons or more. Put your actual tank size into the stocking calculator and it shows what else can live alongside them.
Open the stocking calculatorBefore you buy
Keep your fishies swimming.
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Min. tank: 20 gal
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