At a glance the quick version
Looks how to spot one
Small scaled characin (tetra) with an adipose fin
A slender little tetra marked by two stripes running side by side along the body, a bright white line sitting on top of a wide black band. The top of the eye carries two thin bands of red over yellow. Females are a little larger and deeper in the body than males. A 'diamond' or 'brilliant' variety lacks the white line but has extra shiny scales around the head.32
Personality what they are like
A calm, gentle tetra that mixes well with other small, peaceful fish. It feels most confident and shows its best colour when kept in a decent group alongside other schooling species.2
Daily activity how busy a day looks
Swims mostly in the middle and upper water layers; appreciates open swimming space next to planted cover.1
Grooming and care the hands-on bits
No grooming needed. Keep water clean and stable with regular partial changes; captive-bred fish cope well with mature tap water.32
Home where they are happiest
Tank of at least 60-80 cm long (Seriously Fish suggests an 80 x 30 cm base, about 72 litres). Temperature 23-27 °C (Seriously Fish gives 20-28 °C), pH about 5.0-7.5, soft to moderately hard water up to about 12-15 dGH.12
Food basics what goes in the bowl
Omnivore. Wild fish eat worms, small crustaceans and plant matter; in the aquarium offer a mix of good dry food with live or frozen bloodworm, mosquito larvae, Daphnia or Moina.123
Company who they like around
Keep in a group: FishBase says 5 or more, Seriously Fish recommends a mixed-sex group of at least 8-10.12
The story where it all began
Jacques Géry described the species in 1961 and named it after the American pet-book publisher Herbert R. Axelrod, whose Tropical Fish Hobbyist magazine carried the description. It has been a fixture of the hobby ever since and is bred commercially in several countries rather than collected from the wild.32
Fun facts for the dinner table
- 1
Its scientific name honours Herbert R. Axelrod, the publisher behind Tropical Fish Hobbyist magazine.3
- 2
Look closely and you will see a tiny red-over-yellow band across the top of each eye.3
- 3
In 2023 a black neon tetra 'playing' a Nintendo Switch through motion-tracking software accidentally bought something from the eShop on its owner's account.3
- 4
Eggs scattered in open water hatch in about 24 to 30 hours.1
Recognised by the official bits
- IUCN Red List
- Least Concern (assessed 7 November 2018)1
- FishBase
- Rated highly commercial in the aquarium trade1
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Black Neon Tetra. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- FeedingSmall amounts once or twice a dayevery day
- Temperature checkevery day
- Water changeAbout 25% of the waterevery week
- Water testevery week
- Glass cleanevery week
- Filter rinseRinse in old tank water, never tap waterevery month
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.
- FishBase species summary: Hyphessobrycon herbertaxelrodi (Black neon tetra) fishbase.seused for origin, maximum length, water parameters, natural diet, IUCN status, trade use
- Seriously Fish species profile: Hyphessobrycon herbertaxelrodi seriouslyfish.comused for aquarium size, water parameters, diet, behaviour, group size, sexing, naming
- Wikipedia: Black Neon Tetra en.wikipedia.orgused for other names, appearance, lifespan, history, fun facts
Checked 2026-09-30. Text is written in our own words from these sources.