Neon tetra
A small, brightly colored Amazonian fish popular in home aquariums.
Wikipedia / Wikimedia Commons
The neon tetra (Paracheirodon innesi) is a small freshwater fish from the Amazon basin in South America. It belongs to the American characin family, Acestrorhamphidae, and is the type species of its genus. Its vivid colors help it stand out to other neon tetras in the dark, acidic blackwater streams it inhabits, and this same brightness has made it a favorite among aquarium keepers worldwide.
**Range and habitat** These fish are found in the western and northern Amazon basin, spanning parts of southeastern Colombia, eastern Peru, and western Brazil. They prefer acidic blackwater streams but also live in clearwater streams, avoiding whitewater rivers entirely. Water temperatures in their natural habitat range from 20 to 28 °C (68–82 °F), with a pH between 4 and 7.5. The UN Food and Agriculture Organization lists them as an introduced species in Singapore and the United States, noting that their introduction to Singapore is considered ecologically and socioeconomically beneficial, though they have not become established there.
**Description** The neon tetra has a light-blue back and a silver-white belly. A bright, iridescent blue stripe runs horizontally from its nose to the base of the adipose fin on each side, while an iridescent red stripe starts at the middle of the body and extends to the base of the caudal fin. The rest of the fish, including its fins, is partially transparent. Males and females look similar, but females have a slightly larger belly and a bent iridescent stripe, whereas males have a straight one. At night, the blue and red stripes turn gray or black as the fish rests, then regain their color in the morning. This change happens because guanine crystals in the fish’s cells reflect light differently depending on lighting conditions: in light, the stripe appears blue-green; in darkness, it shifts to indigo. The fish grows to about 4 cm (1.6 inches) in total length.
**Economics** First imported from South America and described by ichthyologist George S. Myers in 1936, the neon tetra was named after William T. Innes. It is one of the most popular aquarium fish, with roughly 2 million sold in the United States each month. Most of these are imported from Southeast Asia, where they are farm-raised, though some are still collected from the wild in Colombia, Peru, and Brazil. Commercial captive breeding in the United States is almost nonex
- Scientific name
- Paracheirodon innesi
- Family
- Acestrorhamphidae
- Order
- Characiformes
- Native range
- Western and northern Amazon basin (southeastern Colombia, eastern Peru, western Brazil)
- Maximum length
- Approximately 4 cm (1.6 in)
- Typical lifespan in aquarium
- Two to three years (up to ten years possible)
- First described by
- George S. Myers in 1936
Lore & Background
The neon tetra was first imported from South America and was described by renowned ichthyologist George S. Myers in 1936, and named after William T. Innes. It is found in the western and northern Amazon basin in southeastern Colombia, eastern Peru, and western Brazil. It lives in waters with a temperature between 20 and 28 °C (68–82 °F) and pH 4–7.5, preferring acidic blackwater streams but also occurring in transparent clearwater streams; it is not found in whitewater rivers. The UN FAO considers P. innesi an introduced species in Singapore and the United States, with its introduction to Singapore deemed ecologically and socioeconomically beneficial, though it is not established there.
Reader's Guide
The neon tetra is one of the most popular aquarium fish, with about 2 million sold in the United States each month. Most neon tetras available in the United States are imported from Southeast Asia, where they are farm-raised, or to a lesser extent from Colombia, Peru, and Brazil, where they are collected from the wild. With the exception of home aquarists and a few commercial farms that breed neon tetras experimentally, captive breeding on a commercial scale is nonexistent in the USA. In the aquarium, they are considered easy to keep in a tank of at least 10 US gallons with a temperature range of 72–76 °F, pH 6.0–7.0, and low hardness. They are shoaling fish and must be kept in groups of at least six. Breeding is considered difficult in home aquariums, though it is becoming more common, with less than 5% of specimens currently sold in America caught in the wild. The species is occasionally afflicted by neon tetra disease, a generally incurable sporozoan disease caused by Pleistophora hyphessobryconis, as well as a bacterial false neon disease that shows similar symptoms.
Did You Know?
- The neon tetra's blue and red stripes become gray or black at night as the fish rests, due to guanine crystals in their cells that reflect light.
- Sexual dimorphism is slight: the female has a slightly larger belly and a bent iridescent stripe, while the male's stripe is straight.
- Neon tetras are old enough to breed at 12 weeks.
- The green neon tetra (P. simulans) and black neon tetra (Hyphessobrycon herbertaxelrodi) are distinct species, not color varieties.
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