Hyphessobrycon herbertaxelrodi – Black Neon Tetra

Hyphessobrycon herbertaxelrodi or Black Neon is a great schooling fish that only schools when threatened. In an aquarium they hardly school.

Hyphessobrycon herbertaxelrodi – Black Neon Tetra

Hyphessobrycon herbertaxelrodi or Black Neon Tetra by its common name, is a nice schooling fish that doesn’t actually school. Unless there is danger, a large school is very spectacular. Both males and females sometimes have small sham fights. In the event of danger, the group forms 1 large school; if you have a group of 30 or more, that is a wonderful sight. Unfortunately, they swim individually for much of the day.

This species was described by Géry in 1961 and has no synonyms. The genus name Hyphessobrycon can be broken into two parts: brykon in Greek means something like a biter or a grinder. Together that means something like a little bitch. The species name is a tribute to Herbert R. Axelrod (1927-2017), tropical fish expert, writer and entrepreneur who has meant a lot to our hobby.


The Black Neon Tetra can reach a total length of around four to five centimeters. They have a brown / beige base color with a bright fluorescent light blue stripe on their flank that runs from behind their opercullum to caudal peduncle. A black bar runs below the blue line and fades downwards. The belly is lighter and yellowish. The upper half of the eye is colored orange.

Males are somewhat slimmer than females and also stay a bit smaller. If you have them in your aquarium for a while, you will start seeing the difference.


Hyphessobrycon herbertaxelrodi - Zwarte Neon Tetra
Hyphessobrycon herbertaxelrodi – Zwarte Neon Tetra

Hyphessobrycon herbertaxelrodi is found in large numbers in the upper Rio Paraguai in Brazil. They occur in the small tributary rivers, the larger rivers and flood areas.


In the wild they feed on small invertebrates, crustaceans, pieces of algae and everything that ends up in the water and is edible. In the aquarium they will eat everything that fits in their mouth, food based on plant-based material is not suitable as main food! Therefore, give them a variety of live and frozen foods combined with flakes and small granules.

The aquarium

Preferably a densely planted aquarium from about 80 centimeters in length. Also an aquarium with a lot of wood, leaves on the bottom (they dig around the leaves looking for food) and long floating plants is very suitable. The fish are most beautiful in a blackwater tank with a dark background. They wil also show their most beautiful colors in blackwater (the white line can even turn greenish!).

A fairly strong surface current and a part where there is hardly any current is advisable. They love to swim against the current, but also like to hang in places without a current.

It is a schooling fish and should therefore be kept in a larger group. Keep them in a group of minimum 12 to 15 fish. In smaller numbers they can become a bit shy. They really seek the safety of the group.

Tank mates

Black Neon Tetras can easily be combined with other species. Just make sure the tank mates are not to big and eat them. Adult Black Neons can be combined with angelfish, they are too big to be eaten but juveniles may end up as expensive food.

Water parameters

pH: 5.5 – 7.5
GH: 1 – 12
Temperature: 20 – 28 degrees Celsius

In the wild, fish have to deal with fluctuating temperatures. Keeping the fish for long times on the suggested minimum or maximum temperatures may shorten their lifespan.

Breeding Hyphessobrycon herbertaxelrodi – Black Neon Tetra

Breeding Black Neon Tetras is not easy. If you use peat in your filter they will get ready to spawn. A group of males will chase one female. The eggs are deposited in fine leaved plants like Java Moss or between the roots of floating plants. I never got my fish to spawn. With some luck they will lay some eggs and with sufficient dense plants a couple of fry will survive.

If you want to breed them it is best to use a special breeding tank. Set up the tank with a sponge filter. This filter will provide just enough current to keep the water clean but won’t suck in the fry. The sponge also provides the fry some food particles to eat from. Cover the bottom with marbles or synthetic grass. Use lots of Java Moss where the parents will lay their eggs. Don’t use fresh tapwater but fill the breeding tank with aged aquarium water. Use water with a pH of around 5.5 to 6.5 and a temperature of 27 – 28 degrees Celsius.

Conditioning and Spawn

Put six to eight females in the breeding tank and condition them with lots of live food such as black mosquito larvae. As soon as they are full of eggs you can add two males. Usually they will spawn next morning. After spawning you will have to remove the parents as they will eat the eggs and fry.

Raising the fry

The newly hatched fry are very tiny. Y0u can feed them with infusoria, Paramecium or a commercial food like Liquifry. As soon as they have grown a bit, you can switch to live cultures of microworms, vinagar eels. A little later start feeding them newly hatched brine shrimp.


When combined with dwarf cichlids pay close attention to the cichlids. Black Neons eat a lot and are very fast. Make sure the slower en somewhat shy dwarf cichlids get enough to eat. A strong water current at the surface may be helpful.

This is a nice and attractive fish for the experienced aquarist. Despite being a food competitor they make a great tank mate for dwarf cichlids.



John de Lange

Copyright images

John de Lange

Additional information





Social Behaviour

Breeding behaviour






Minimum aquarium length in cm

Length maximum in cm

Temperature minimum

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pH minimum

pH maximum

GH minimum

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