Paracheirodon innesi
Hardy beginner classic. Looks dull in bright tanks, dark substrate and floating plants bring out the neon stripe. Keep in groups of 10+ for natural shoaling behaviour.
Neon Tetra (Paracheirodon innesi) reaches 3.5–4 cm as an adult and needs a minimum tank of 60 L. Native to Upper Amazon basin, South America, it lives in the mid water column with a peaceful temperament. Aim for 20–26 °C, pH 5.5–7.0, and 1–8 dGH hardness. Lifespan is 5–8 years with good care. Keep neon tetra in groups of 10+, yes schoolers need numbers to display natural behaviour. Diet: omnivore, Crushed flake, micro pellets, daphnia, baby brine shrimp. Eats 1–2x daily. Plant-safe: Yes. Shrimp-safe: Yes (with adults; may eat shrimplets).
Care at a glance
Hardy beginner classic. Looks dull in bright tanks, dark substrate and floating plants bring out the neon stripe. Keep in groups of 10+ for natural shoaling behaviour.
By Mike ElmiraUpdated 3 min read
Part of our complete guide to aquarium fish for the planted tank.
The parameters that decide whether neon tetra fits in your tank.
Mid
Yes
Group of 10+
Characidae
Omnivore
Crushed flake, micro pellets, daphnia, baby brine shrimp. Eats 1–2x daily.
5–8 yrs
Hard
Slow blackwater forest streams of the Amazon basin
Upper Amazon basin, South America
Tank-mate safety and the species this one is documented to thrive (or fail) alongside.
Corydoras pygmaeus, ember tetras, otocinclus, chili rasboras, sparkling gouramis, cherry shrimp (adults).
Angelfish (predator), barbs (fin nippers), bettas (mostly), bigger cichlids, anything over ~6 cm.
Hard-won lessons from the tank.
Buy from a single source, not mixed sources — disease risk compounds. Acclimate over 60+ minutes via drip. A group of 15–20 in a planted 75-litre tank looks far more impressive than 6 in a 30-litre — schooling behaviour shows best at scale.
Genus 'Paracheirodon' = 'near Cheirodon' (a related characid genus). Species 'innesi' honours William T. Innes, American aquarist and publisher who popularised the fish in the 1930s.
What can go wrong and how to spot it.
Failure modes, in order of how dramatic the fix is.
Neon Tetra Disease (Pleistophora hyalinosomatis) — incurable microsporidian; symptoms are fading colour, lumpy body, erratic swimming. False NTD (similar look but caused by Mycobacterium) also exists. Both are contagious — quarantine new fish for 4 weeks.
Often confused with cardinal tetra (P. axelrodi) — neon's red stripe only runs from mid-body to tail; cardinal's red runs from snout to tail. Neon is hardier than its reputation suggests once acclimated, but stock from cheap mass-producers is often weak.
The practical routine, read top to bottom.
30–60 L planted nano. Dark substrate (black sand or ADA Amazonia). Heavy floating plants for shade. Driftwood and Indian almond leaves (catappa) for tannins. Dim, indirect lighting. Sponge filter or low-flow canister — they hate strong currents.
4 weeks minimum in a bare-bottom QT tank with sponge filter. Watch for NTD signs and treat for ich preventively if temperature changes were involved in transport.
Where it comes from, how it behaves, and the variants you'll see at retail.
Where it lived before it came home.
Slow-moving, deeply shaded blackwater streams and tributaries of the upper Amazon basin (Peru, Brazil, Colombia). Tannin-stained, very soft, acidic water (pH 3.5–6.5 in the wild), heavy leaf litter, dense submerged roots.
Tiny crustaceans, insect larvae, fallen invertebrates, microscopic algae and biofilm.
Not threatened — most farmed in Southeast Asia. Wild caught from Peru still occurs but represents a small fraction of the trade.
How they pair, reproduce, and grow.
Females are noticeably plumper from above, especially when conditioned. Males have a straighter blue line; females' line is slightly curved over a fuller belly. Both sexes show identical colour intensity.
Triggered by very soft (<2 dGH), acidic (pH 5.0–6.5), tannin-rich water dropped to 22–24 °C and dim lighting. Egg scatterers — adults will eat eggs and fry. Use a fine spawning mop or Java moss; remove adults after spawning. Eggs hatch in 24–36 hours; fry are tiny and need infusoria for the first week.
The named cultivars and the lookalikes worth flagging.
Wild type only — 'long-fin' and 'diamond head' variants exist but are uncommon and often weaker. Avoid 'glofish'/dyed neons on ethical and welfare grounds.
Direct answers to the questions search engines and AI assistants surface most often about this species.
Neon Tetra (Paracheirodon innesi) needs a minimum tank of 60 L. They live in the mid water column and should be kept in groups of 10+, so a longer footprint matters more than depth.
Target 20–26 °C, pH 5.5–7.0, and 1–8 dGH hardness. Acclimate slowly when moving them between water sources.
Shrimp safety: Yes (with adults; may eat shrimplets). Plant safety: Yes.
Neon Tetra are omnivore. Crushed flake, micro pellets, daphnia, baby brine shrimp. Eats 1–2x daily.
On Fin & Stem's 1–5 difficulty scale this species rates 2/5. Forgiving, beginner-friendly once the tank is cycled. Breeding difficulty: hard.
Typical lifespan in a well-maintained tank is 5–8 years.
A planted tank is a system. Pair this fish with one entry from each other pillar to plan the whole scape.
