Black Neon Tetra (Hyphessobrycon Herbertaxelrodi): Ultimate Care Guide

The black neon tetra (Hyphessobrycon herbertaxelrodi) is a freshwater fish of the characin family, order Characiformes. They are natively found in the Paraguay basin of southern Brazil and, as the name would suggest, they closely resemble the neon tetra (Hyphessobrycon). Their taxological name is in honor of Herbert Axelrod, a pet-book publisher whose magazine first described this fish.

Black neon tetra have the typical elongated appearance of most tetra species, a basic coloration of white, greenish and black, with two longitudinal stripes on the abdomen, one white and one black. The eyes also possess a pair of color bands above them. In this case, a red line above a yellow one.

They are known to grow to a maximum length of 1.6 inches. With females growing slightly larger than male specimens and with a more rounded belly, but the small size of this species makes them difficult to tell the genders apart.

In the wild, they enjoy small tributaries, sandbanks, flooded forests, and creeks. Their natural habitat is very acidic and stained brown from the overabundance of organic matter.

Black Neon Tetra Care

Black Neon Tetra are not particularly difficult to take care of. However, there are certain care requirement that must be met.


The water should be around 68 to 82 degrees Fahrenheit, though 75 degrees is ideal.

Water pH

Black Neon Tetra are found in waters that are usually stained brown with fallen and decayed leaves, which raises acidity levels. You don’t have to actually stain the water in your aquarium to make them happy, but you should stick to a pH level of 5.0 to 7.5 and maintain your water at a hardness of 6dGH.

Keeping the pH at an optimal level is crucial for the first few days of transfer into a new tank. Drastic changes in the pH level while they are still getting adjusted can put the fish under stress and make it harder for them to survive in the coming days.

Black Neon Tetra (Hyphessobrycon Herbertaxelrodi)
Black Neon Tetra (Hyphessobrycon Herbertaxelrodi)

Black Neon Tetra Size

Black neon tetra usually only reach an average size of about 1.5 inches. Some have been known to grow as large as 1.6 inches, but that is a rare occurrence.

Food and Diet

Black neon tetra are omnivores, so they can eat a wide variety of different foods, as long as they can fit them in their tiny mouths. Small crustaceans, algae, and plant matter are their common foods in their natural habitat. In your tank, you can provide them with a nicely balanced diet of dry flakes or pellets. Then supplement their diet with brine shrimp, bloodworms, mosquito larvae, and similarly protein-rich foods. Just be careful not to overfeed them. Be sure to cut up larger foods like worms or shrimp to make it easier for them to consume.

Feed your black neon tetra twice a day for three minutes each as young adults. Then once a day when they have matured.


Black neon tetra will reach an average lifespan of roughly five years if properly cared for.  Though they are very hardy fish and live longer than other species of tetras if they don’t get the right conditions then they won’t live for very long.

Tank Size

Since they are such a small species of fish, black neon tetra don’t require a great deal of tank space in order to be happy. Keep in mind that they are schooling fish, so you’ll likely want to keep a group of at least half a dozen of them together. Even then a tank of only 20 gallons will be enough to give them their space. Though they certainly won’t complain at having more room to explore.

If keeping other types of fish in the tank alongside them you will, of course, require a larger tank as appropriate to the other species you have.

Tank Setup

In order to give your black neon tetras the best environment to live in you will naturally want to recreate their habitat in the wild as best as possible.

The first step is to layer the tank with a substrate of sand and dark gravel, even though black neon tetras rarely swim down to the bottom of the aquarium. They tend to prefer the upper and middle regions. However, this is similar to their normal environment.

Lighting in the tank should also be subtle and low. This is not only to replicate their environment but also because the shadowy ambiance will highlight the iridescence of their scales the best.

It’s also important to select a wide variety of different live plants in order to provide them with thick vegetation. Restrict it mostly to the background, however, so that they have space for swimming in the center. Accent these with driftwood and rocks to provide them with shelter from the light. You can also distribute some plant leaves on the bottom, which will mimic their habitat more and stain the water brown by releasing tannin into the tank.

Since you’ll likely be keeping your black neon tetras in schools you need to take waste into consideration as well. A single small fish produces very little waste, but in groups, it can become an issue. So make sure that you have good water filtration. Too much waste can have an effect on ammonia and nitrate levels. Your filter should produce a strong flow near the top of the tank. Many owners also like to add peat moss to the filtration system as well. Some say that it brings out the coloration of the fish.

Black Neon Tetra Breeding

Black neon tetras can be easily bred. The spawning will occur naturally in the tank, but to ensure the survival of the young fish it is best to set up a separate breeding tank for them. A small tank (about 10 gallons is more sufficient) with a dark sand substrate, lots of plants, and low lighting is best before you introduce your bonded pairs into it.

Feed your pair live, protein-rich foods and slowly raise the temperature to 80 degrees Fahrenheit over the next few days to trigger spawning. Maintain soft water with a hardness of about 2-4 dGH and acidity of around 6pH.

Once pregnant, the female can lay hundreds of eggs at once. Then scatter them onto the substrate or stick them on the underside of leaved plants. A mop-like bundle of yarn or synthetic fabric can also be placed into the tank for them to attach their eggs to. It is easier to clean and won’t decompose or rot in the tank.

The eggs can be expected to hatch in between 22 to 26 hours. Make sure that during that time the parents are removed from the tank to prevent them from preying on their own young. Alternately you can place a mesh, grass-like mat, or some other barricade to separate the parents from the eggs once they are laid.

For the first few days, expect the fry to subsist on their own egg sac until they are large enough to eat on their own after the third or fourth day. Then feed them foods like baby shrimp or infusoria. Once the babies have reached the same size as the adults they can be safely placed back into the main tank with the adults.

Black Neon Tetra Diseases

Black neon tetra are a hardy species but aren’t immune to disease. It’s important to note that black neon tetras can carry a disease called “neon tetra disease”. Which is technically a parasitic infection that fish can get from other infected fish. This can quickly spread throughout the tank and there is no known cure for this.

Neon tetra disease infects the fish with a parasite that eats the muscles from the inside out once it reaches the intestinal tract. Symptoms include abnormal individuality in schooling fish, cysts, difficulty in swimming, inflamed abdomen, and curving of the spine. Be sure to immediately quarantine any fish you suspect of being infected with this as you will not be able to keep them anymore.

Be sure to keep your water of extremely high water quality after the outbreak occurs.

Another common problem with black neon tetras is obesity caused by overeating. This can cause a deterioration in their organ function so it is very important to monitor what the fish eats. Avoid this by keeping the portion sizes small and consistent. Generally, they should be fed bits of food small enough for them to finish in under three minutes two times a day for young adults and once for mature fishes. Doing this will also reduce the amount of organic waste you have to deal with in your aquarium.

They are also susceptible to the normal diseases you can find in any fish species. Of special note are Ich, and fish dropsy.

Ich is a stress-related disease caused by parasites. You can recognize it by tiny white dots scattering over the fish’s body. It is contagious but very easy to treat with over-the-counter medications. Just remember to quarantine infected fish first. Ich can also be a result of poor water conditions, so check ammonia, temperature, and pH balance conditions for your tank to make sure they are in an acceptable range.

Fish dropsy is a typical fish disease caused by bacterial infection of the kidneys. The condition causes fluid retention in the kidneys, causing the fish to take on a bloated appearance. You can treat this with antibiotics and proper care. Be sure to monitor your ammonia and nitrate levels in the tank carefully to make sure they are at proper levels.

Naturally, the best way to deal with disease is to prevent it from occurring in the first place. Maintain good tank conditions and replace 30-50 percent of the water every two weeks to ensure a healthy environment for your fish.

Black Neon Tetra Tank Mates

When picking your tankmates you’ll obviously want to choose mates that are small and non-aggressive. Larger fish will just consider your black neon tetras to be a very pretty meal. A nice, peaceful tank is essential to keeping these fish healthy.

The best tankmates will be other black neon tetras. At the very least keep a group of about half a dozen together since they are social fish and need other friends. If they are left alone they can become stressed and when stressed their colors will begin to fade.

Chili rasbora, harlequin rasbora, celestial pearl danio, rummy nose tetra, neon tetra, small freshwater catfish, honey gourami, dwarf gourami, sparkling gourami, and freshwater snails (the fish won’t bother them as long as they are well-fed) also can make great tankmates for them.

It is also possible to keep black neon tetras and betta fish together in the same tank as well. The colors of this species will not trigger the betta’s aggression. However, you should monitor the situation just in case to be certain they are playing nice.

Pygmy catfish can also be a good idea to act as tankmates. Since black neon tetra prefer to swim around the tops of the tank, the presence of bottom-feeding fish like catfish is good for picking up food that falls to the bottom to prevent waste.

Other tetras, like the basic neon tetra, can generally also be kept in the same tank with your black neon tetras, but it is important to make sure that you have similar numbers so that they form proper schools.

Whatever tankmates you decide to add, be sure to cross-check the water parameters so that all your fish are compatible.

Black Neon Tetra Behaviour

Black neon tetra are generally peaceful and will get along with other fish that share their temperament. They never show aggressive behavior towards other fish.

They like to swim out in the middle and top of the tank, and are very energetic when swimming. Be aware they are also very skilled jumpers and may try to show off for you if given the chance. Be sure to keep your tank covered or they may jump right out of it.

Where to Find Black Neon Tetra for Sale?

Black neon tetra that are available for sale are generally bred in captivity and can be found in most stores.  Generally these fish cost between $2 to $4 each. There is also an albino variant that can be found in some places.