rm
Passport
- Family
- Tetras
- Grows to
- 2.5 cm (1")
- Lives
- 2–3 years
- Temperament
- Peaceful
- Care
- Intermediate
- Swims
- Mid-water
- Keep
- In a group of 10 or more
- Water
- 21–35 °C (70–95 °F)
BrazilColombiaVenezuela
Care requirements
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On record for Green Neon Tetra: adult size, lifespan, minimum tank, temperature, ph, hardness, minimum group, diet, care level, swim level, tank length.
A figure that is not on record is left out rather than guessed. One marked Suggested comes from keeping knowledge rather than a page.
- Minimum tank 57 L / 15.0 US gal
- pH 3–6.5
- Hardness 1–8 dGH
- Diet omnivore
- Tank length 45 cm minimum
Care notes written from general aquarium knowledge, not from the cited sources.
About
Green neons are the specialist of the three neon-type tetras, and they're not a beginner's fish despite looking like one. Smaller than a neon, with the blue-green stripe running almost the full body and only a wash of red near the tail, they're the subtlest of the family and the most demanding.
Every one you buy was caught wild. Nobody breeds them commercially, which makes them scarcer and dearer than neons or cardinals, and it means the fish arriving in your tank has had a hard trip and needs a settled, mature aquarium waiting for it.
They live exclusively in blackwater — not merely tolerating it like a cardinal, but found nowhere else. Their home streams are extraordinarily acidic and almost devoid of dissolved minerals, and they've been recorded in water far hotter than most tropical fish would survive, which is why their temperature range looks so improbably wide.
Tank setup
Build your green neons a blackwater tank and nothing else. Sand, wood, roots and a deep layer of dried leaves, tinted the colour of strong tea, under dim light. This is the one species here where the biotope isn't a stylistic choice.
Keep the water very soft and genuinely acidic. Alder cones and leaf litter will get you there naturally; there's no need for peat, whose harvesting does real environmental damage.
Never put them in a new tank. They're acutely sensitive to immature filtration and to conditions that shift, and post-import fish have no reserves to spare.
Keep them on their own or with very small, quiet company. They're too small and too particular to hold their own in a general community.
Feeding
Green neons take small live and frozen food eagerly and dried food reluctantly. A tiny fish with a tiny mouth needs everything graded down.
Feed daphnia, moina, baby brine shrimp and small bloodworm as the mainstay, with a fine dried food filling in. Wild-caught fish in particular often ignore flake entirely for their first weeks.
Feed lightly and often. Their capacity is minuscule and uneaten food in a soft, acidic, lightly filtered tank is a real problem.
Avoid: anything coarse, and any expectation that they'll adapt to a pellet.
Filtration and flow
Keep the flow slow and gentle. They come from slow forest headwaters and they're weak swimmers even by small-tetra standards.
An air-driven sponge filter is the right tool. It moves water without pushing the fish around, it won't strip the tannins, and it's safe with anything small.
Be careful with water changes. Very soft acidic water has almost no buffering, so pH can move fast, and matching the replacement water properly matters more here than in any ordinary community tank.
With plants
Green neons are entirely safe with plants, and the constraint is the light rather than the fish. Under the dim conditions they need, only low-light plants will survive.
Java fern, java moss and cryptocorynes all cope. Floating plants are worth adding for the shade as much as the greenery.
Leaf litter does more for this species than any planting will. It stains the water, grows the microscopic life they pick at, and gives them the cover they expect.
Health
They're delicate on arrival and hardy once settled, and almost every loss happens in the first weeks. Quarantine if you can, acclimatise slowly, and accept some attrition on wild-caught stock.
Neon tetra disease occurs in this species too. A fish losing colour in patches, drifting away from the group and wasting is the pattern, and there's nothing to be done but remove it.
Watch for fish sitting near the bottom with clamped fins after a water change. That's usually a chemistry swing rather than an infection, and it's the commonest avoidable killer here.
Breeding
This is genuinely hard, and it's why nobody farms them. The eggs need water softer and more acidic than most keepers can produce from a tap, and outside that window they simply fail.
If you want to try, you need a dedicated tank, water treated by reverse osmosis and re-acidified with botanicals, near-total darkness, and fine-leaved plants or a mesh floor. The adults eat the eggs, so they come out immediately.
The fry are among the smallest of any aquarium fish. They need infusoria in real quantity before they can manage anything else, and getting them through that first week is the whole challenge.
Tank mates
Avoid11
- Convict Cichlid Convict Cichlid grows to 15 cm against Green Neon Tetra at 2 cm, big enough to eat it.
- Jewel Cichlid Jewel Cichlid grows to 15 cm against Green Neon Tetra at 2 cm, big enough to eat it.
- Kribensis Kribensis grows to 8 cm against Green Neon Tetra at 2 cm, big enough to eat it.
- Panda Garra Panda Garra grows to 9 cm against Green Neon Tetra at 2 cm, big enough to eat it.
- Pictus Catfish Pictus Catfish grows to 12 cm against Green Neon Tetra at 2 cm, big enough to eat it.
Only with care10
- Chinese Algae Eater Chinese Algae Eater is aggressive and Green Neon Tetra is peaceful.
- Cherry Barb Cherry Barb is a risk to Green Neon Tetra: barbs and tetras are a pairing to watch.
- Gold Barb Gold Barb is a risk to Green Neon Tetra: barbs and tetras are a pairing to watch.
- Odessa Barb Odessa Barb is a risk to Green Neon Tetra: barbs and tetras are a pairing to watch.
- Paradise Fish Paradise Fish is a risk to Green Neon Tetra: large gouramis and tetras are a pairing to watch.
No conflict is recorded with the other 85 species in the database, so nothing to flag. 2 species are not covered at all, so they could not be judged either way.