Neon Tetra
Paracheirodon innesi
The Neon Tetra (Paracheirodon innesi) is without a doubt the most known and iconic freshwater aquarium fish in history, whose popularity has defined the hobby itself since its arrival on the market in the 30s. Famous for its minute dimensions (about 3-4 cm / 1.5 inches) and its derisory price, it sports a dazzling iridescent blue-turquoise band above a red stripe. However, unlike its 'Cardinal' cousin, the red stripe in the Neon abruptly stops mid-flank, leaving the belly and throat a clean silver-white. Although proposed in every store as the first fish for beginners, very few know that the Neon is a fish from decidedly cooler climates compared to the rest of the Amazonian fish, and often dies prematurely if boiled in tanks at extreme tropical temperatures.
Water Temperature
20 - 24 °C
pH Value
5 - 7.5
Water type
Freshwater
Tank level
Middle
Adult size
4 cm
Minimum tank volume
>= 60 L
Minimum group
>= 10
GH
1 - 10 dGH
KH
1 - 4 dKH
TDS
25 - 190 ppm
Conductivity
39 - 297 uS/cm
Species description
Geographical Origin and Habitat: The Neon Tetra originates from western Amazonia, specifically in parts of Peru, Colombia, and western Brazil. It typically inhabits slow-flowing, shaded streams and tributaries under the dense canopy of the rainforest, where the water is soft, clean, and cool, often running over leaf litter.
Taxonomy and Morphology: Belonging to the Characidae family, it is a small, slender species reaching 3-4 cm in length. It is easily distinguished from the Cardinal Tetra (*Paracheirodon axelrodi*) by the length of its red coloration; the Neon Tetra's red stripe only extends from the tail to the mid-flank, leaving the throat and anterior belly a reflective silver-white.
Social Behavior: It is a peaceful, schooling fish that must be kept in a group of at least 10 individuals to feel secure. In the aquarium, tight schooling is generally observed when they feel threatened or when introduced to moderate water currents, whereas they scatter in calm conditions while keeping in visual contact.
Coloration and Sexual Dimorphism: Straight Stripe = Male: Given the swarming school, there is no need to catch them if you want to determine the sex. Stare at the stomach. If the fish has an almost explosively round belly and the neon blue line suffers a conspicuous hook-like "bend" up or down for this reason, it is a female.
Care, breeding and tankmates
Aquarium Setup: A minimum tank size of 60 liters (15 gallons) is recommended. The setup should feature a dark substrate, driftwood roots, and plenty of live plants. Floating vegetation is highly recommended to diffuse the light, which mimics their natural shaded habitats and encourages active swimming.
Diet and Feeding: Omnivorous and opportunistic in nature. Due to their tiny mouths, they must be fed small-sized foods such as high-quality crushed flakes, micro-pellets, or live/frozen foods like daphnia, baby brine shrimp, and rotifers. Feed in small amounts to prevent digestive complications.
Water Quality: Turn Off That Heater (Death by Hot Water): This is why your Neons die one at a time after two months. This little fish IS NOT a hot water fish at 28 degrees (82°F). Unlike its Cardinal cousin (with which it is constantly confused and exchanged at equal water parameters), the Neon comes from the cool shaded streams of Peru. Its ideal temperature is between 20°C and 22°C (68-72°F). The boiling water of a common tropical aquarium will destroy its kidneys and horribly shorten its life. They live peacefully at room temperature in houses.
Compatibility and Cohabitation: Flying Snacks (Never Put in with Angelfish): There is a horrible aesthetic trend of creating huge aquariums with very tall Angelfish surrounded by a nice school of very small blue Neon Tetras to make a visual contrast. Wrong. In nature (on the Amazon River) the Angelfish literally has a mouth conformation purely evolved to swallow a Neon alive in a fraction of a second. It is literally its favorite food. You will buy fish only to feed the predator.
Aquarium Breeding: Breeding requires a separate spawning tank with very soft, acidic water (GH and KH close to 0, conductivity below 20 µS/cm). Use spawning mops or fine-leaved plants. The eggs are highly light-sensitive and will deteriorate if exposed to light; keep the tank dark until the eggs hatch.
Risks and Diseases: Neon Tetra Disease (NTD): Being the most mass-bred animal, their genes have weakened over the years. They are the number one patients of the deadly parasite *Pleistophora hyphessobryconis* (which takes its commercial name from them). If one day you see that one of your Neons in the school "fades", loses the blue stripe, its skin becomes opaque and it moves away from the group unable to swim straight, YOU MUST REMOVE IT AND EUTHANIZE IT IMMEDIATELY before it dies, otherwise, as soon as the sick one stops breathing, the entire school will cannibalize its corpse catching the deadly disease.
Geographic Origin and Distribution
The Neon Tetra originates from western Amazonia, specifically in parts of Peru, Colombia, and western Brazil. It typically inhabits slow-flowing, shaded streams and tributaries under the dense canopy of the rainforest, where the water is soft, clean, and cool, often running over leaf litter.
Origin
Tropical oceans and reefsAmazon, Orinoco, and Guianas
Fish profile
- Temperament
- Peaceful
- They are highly gregarious and peaceful schooling fish. They feel most secure when surrounded by their own kind. Without a school, they become highly stressed and timid.
- Diet
- Omnivore
- They are omnivorous micro-predators in the wild. In the aquarium, they accept crushed flakes and micro-pellets. Supplement with live or frozen daphnia for optimal health.
- Life expectancy
- 5 years
- In captivity, the Neon Tetra has an average lifespan of 5 to 8 years under proper care conditions. Because they originate from slightly cooler waters compared to Cardinal Tetras, keeping them at moderate temperatures slows their metabolism, which benefits their longevity. Maintaining highly stable water parameters and rigorous tank hygiene are decisive factors in ensuring a long and healthy life.
- Adult size
- 4 cm
- The catalog's scalar value is 4 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 2.22 cm for this species, recorded as standard length (SL). The taxonomic record consulted is Paracheirodon innesi (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- School
- Sex ratio is unimportant in a decent sized school. Keeping a mix of males and females is completely natural. Always keep them in groups of at least six.
- Feeding frequency
- Twice daily
- Feed them small amounts once or twice a day. Provide only what they can consume within two minutes. Overfeeding can quickly pollute their small environment.
- Bioload
- These small tetras have a very low bioload. They generate minimal waste in the aquarium. Standard filtration is usually more than enough.
- Flow
- Stagnant
- They prefer gentle to moderate water flow. Harsh currents can exhaust these small fish and cause stress. A sponge filter creates an ideal slow-moving environment.
- Jump risk
- No
- Reproduction
- Egg scatterer
- They are egg scatterers providing no parental care. Breeding requires very soft, acidic water and dim lighting. Parents will consume their own eggs if not separated.
- Compatibility & tankmates
- Peaceful
- They are exceedingly peaceful community fish. Keep them only with similarly sized, non-aggressive species. Large predatory fish will easily swallow them whole.
- Tank level
- Middle
- These tetras swim in the middle levels of the water. They appreciate open swimming areas and dense vegetation. They rarely venture to the absolute surface or bottom.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 2.9 ± 0.32 se
- Resilience
- High (less than 15 months)
- Phylogenetic uniqueness (PD50)
- 0.625
- Bayesian Length-Weight
- a = 0.01122, b = 3.07
- VulnerabilityLow vulnerability (10 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
Related species
Recommendations grouped by close relatives, companion choices, and similar care.
