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No federal permit to keepGreen neon tetra
Paracheirodon simulans
Fishes › Tetras, piranhas and pacus (Characiformes) › Characidae (Tetras)
The green neon tetra (Paracheirodon simulans) is a species of freshwater fish of the family Acestrorhamphidae, the American characins, of the order Characiformes.
Care at a glance
Species-specific aquarium care
- Tank: At least 24 in long and 12 in front to back for one adult (adults commonly reach about 0.8 in / 2.02 cm).
- Water: Freshwater.
- Temperature: 73–81°F (range recorded for this species).
- pH: 5.5–6.
- Hardness: 0–4 dGH.
- Layout: An open-water swimmer: needs long, open swimming space with few obstacles.
Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.
Care guide
Species care notes
- Tank: a base of at least 18 × 12 in (roughly 11 US gallons); space needed is rated “modest tank”.
- Water: soft, acidic water, 70–95 °F, pH 3–6.5, 1–8 dGH.
- Behaviour: temperament peaceful; a shoaling fish best kept in a group of six or more; suited to a community tank.
- Difficulty: Easy (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Maintenance generally presents few problems although a degree of care is necessary since fish in the trade are exclusively collected in the wild and can be sensitive, especially post-import.”
- Diet: “Likely to be omnivorous feeding on small invertebrates, crustacea, filamentous algae, fallen fruit and suchlike in nature.”
- Tankmates: “Peaceful with other species but does not make an ideal community fish due to its small size and somewhat specialised requirements Ideally it should be maintained alone or at most with diminutive, non-aggressive characids and smaller callichthyid or loricariid…”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Tetras
Applies to most species in this group. Habitat: The covered characids include South American river and tributary fishes, from vegetation-shaded bloodfin habitats to sandy flowing rivers occupied by Exodon. [fg156-bloodfin, fg156-exodon]. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- For glass bloodfins, use at least 60 × 38 × 30 cm (24 × 15 × 12 in), retaining open upper-water swimming space.
- Provide planted margins and floating vegetation for bloodfins; fit a tight lid for Aphyocharax anisitsi.
- For bucktooth tetras use at least 120 × 45 × 45 cm (48 × 18 × 18 in), efficient filtration and planted refuges from bullying.
- For glass bloodfins maintain pH 6.0–7.5; for Exodon, pH 5.5–7.5.
Climate & lighting
| Water | 73.4–80.6°F |
Diet
- Small dried foods for glass and ordinary bloodfins.
- Daphnia, Cyclops and bloodworms for glass bloodfins.
- For Exodon, chopped prawns, mussels, earthworms and fish rather than live feeder fish.
Social life
- Glass bloodfins need 6–8 or more; ordinary bloodfins at least six. Exodon requires a species aquarium and at least 12 introduced together; small groups can kill one another.
Health watch
- Freshwater ich (white spot disease), a general aquarium risk.
- Bacterial infections associated with stress and poor water quality.
- Fin and scale damage from aggression, especially Exodon.
Understanding the animal
About this animal
About this animal
It is native to the upper Orinoco and Negro Rivers in South America.
Quoted from the Wikipedia article “Green neon tetra” (CC BY-SA 4.0) 174
In the wild
In the wild
From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.1
| Where it lives | Lives in freshwater. |
| Water it lives in | Freshwater, 73–81 °F (23–27 °C), pH 5.5–6, hardness 4 dH. |
| Climate | Tropical climate. |
| Behavior to plan for | Breeding: open water/substratum egg scatterers. |
What this means for care
- Keep water within its wild range, 73–81 °F.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 91°F (up to 95°F in the hottest sampled areas) |
| Cool-season lows | about 70°F (down to 69°F in the coldest sampled areas) |
| Average temperature | 79–81°F across sampled records |
| Relative humidity | 78–85% on average (driest month about 78%) |
| Rainfall | about 2398 mm a year |
Measured at 22 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.
From the sources
From the sources
Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.
| Overview | The green neon tetra (Paracheirodon simulans) is a species of freshwater fish of the family Acestrorhamphidae, the American characins, of the order Characiformes. It is native to the upper Orinoco and Negro Rivers in South America. — Wikipedia (community-edited) |
| Where it lives | Home ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase |
| Social life and communication | Green neon tetras transmit sound energy to the auditory organ by the use of a Weberian apparatus. — Animal Diversity Web |
| Wild diet | Paracheirodon simulans is omnivorous. — Animal Diversity Web |
| Behavior | There is little information on the behavior of P. simulans. — Animal Diversity Web |
| Reproduction | Spawns better in schools than pairs. — FishBase |
| Lifespan | The longevity of green neon tetras has not been reported. — Animal Diversity Web |
| Appearance and size | Green neon tetras appear similar to neon tetras, Paracheirodon innesi, although they are smaller and the red patch on the lateral body is less pronounced. — Animal Diversity Web |
| History and naming | The green neon tetra was originally described as Hyphessobrycon simulans in 1963. It was integrated into the genus Paracheirodon in 1983, along with the cardinal tetra on the basis of morphological similarities. This change is now supported by molecular studies. — Wikipedia (community-edited) |
| Conservation | Paracheirodon simulans is not listed by CITES or IUCN as a conservation concern. — Animal Diversity Web |
Data and studies
The numbers
The numbers
Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.
Adult length
Maximum recorded length. Measured as standard length (snout to the base of the tail, not counting the tail fin). Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates in nature; aim for the middle.
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 18 × 12 in (about 11 US gallons).
Sources for this sheet
- FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
- Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
- Seriously Fish: Prionobrama filigera Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Exodon paradoxus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Aphyocharax anisitsi Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Merck Veterinary Manual: Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
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