Buenos Aires tetra care guide

Buenos Aires tetra (Hyphessobrycon anisitsi) is not a picky one at all, it lives long and is easy to breed. The fish is quite hardiest and adapts well to most of tank water parameters and so it doesn’t require any special keeping conditions. This is a perfect fish for beginner aquarists. However, it has some peculiarities in terms of keeping you have to know to keep the fish successfully. This and many other information you will find in our article.

Habitat in the wild

First the Buenos Aires tetra was described by an ichthyologist Carl Henry Eigenmann in 1907. Buenos Aires tetra dwells in South America in Paraná and Uruguay river basins. This is a schooling fish, that lives in large amount of biotopes including: rivers, streams, lakes and ponds. In the wild it feeds on insects and fouling.

Scientific NameHyphessobrycon anisitsi
Common NamesBuenos Aires tetra; red cross tetra; red cross fish
Range and habitatSouth America
Size7.5 cm (3 inches)
Lifespan5 years
Ease of keepingEasy
Minimum tank size80 liters (20 gallons) and more
Temperature72-78 °F (22-26 °C)
Water hardness5-20 dGH


If compared with other tetra species it is quite a large fish. Its body length can be up to 7 cm (2.8 inches). At that the lifespan is up to 5 years and more.

The Buenos Aires tetra body coloring is silvery, the back is brown and olive, dorsal, anal and abdominal fins are reddish or yellowish. The upper side of the fish iris is red. There is a dark diamond shaped spot near the tale fin base.

Albinotic species of Buenos Aires tetra was also bred. It is more thermophilic and less aggressive. There are also species with long fins.

Difficulties in keeping

The Buenos Aires tetra is good for beginner aquarists, since it is rather simple in care, enduring and doesn’t need any special tank conditions. But…

Buenos Aires tetra nips other fishes fins as well as it may crop soft and delicate tank plants. So you should be careful when keeping it planted tanks. The tank should be closed with a lid, because the fish can jump out of the water.

You should keep them in a school not less than 7 species; if there are less of them, they will demonstrate aggression towards their tank mates. Besides this red cross tetra is very timid and if it feels danger, the whole school hides among thick tank plants. The fish may also show aggression towards its kind.

Care and keeping in a tank

Since the fish is undemanding, keeping Buenos Aires tetra even in a community tank isn’t a difficult or troublesome thing to do. However, you should keep in mind that the fish may be aggressive and it’s better to provide it with fast and equally sized tank mates.

There are no special requirements to the bottom substrate or to the tank lighting. However, the tank has to be tightly closed since the fish may jump out of it.

In general, the Buenos Aires tetra is completely not picky. As for the tank conditions: regular water renew is a must, desirable water parameters are: temperature 72-78 °F (22-26 °C), pH 6.0-8.0 , 5 — 20 dGH.

However, keep in mind that the Buenos Aires tetra eats almost all kinds of tank plants except maybe java moss and anubias. If presence of greenery in a tank is crucial for you, tetra is definitely not your type of fish. You can reduce their craving for eating tank plants by adding food with high vegetable content into the diet.


The Buenos Aires tetra isn’t demanding in terms of food – it eats frozen, live and artificial food.

Though it prefers live food, especially daphnia; it catches bloodworm while it is falling to the tank bottom. It doesn’t like eating food from the bottom and that’s why it’s better to feed it with slowly drowning food types, that it will gradually eat.

This tetra crops fresh shoots of tank plants. Therefore, including vegetable food into the diet is a must.

Tank mates

Buenos Aires tetra swim in schools and they are active all the time. At the slightest sign of danger the whole school hides in tank plants. Keeping the fish in a school of its kind is what reduces its natural aggressiveness.

However, slow and long finned fishes (goldfishes, angelfishes, guppies) will anyway suffer when dwelling in one tank with Buenos Aires tetra.

In general, the fish is quite suitable for a community tank. It is active and if there a lot of them, they stay in a school. But as for tank mates, these should be other fast and active species, for example: zebra danio, tiger barb, rosy barb.

Gender differences: male vs female

Buenos Aires tetra male is thinner and has brighter colored fins. The females are larger than the males; you can recognize them by their rounded abdomen.


Prepare a small tank (up to 20 liters capacity) with fresh settled water for breeding. It’s good if the tank is elongated, 25-30 cm high. Leave its center empty and put some tank plants near the walls.

When everything is ready, put a female and two male there. The Buenos Aires tetra should live separately for several days before this. At first the female wards off the males and they stay on the other side of the tank.

This can last for a day and sometimes longer, till reproductive products get ready. Then, usually in the morning, the males start haunting the female fish and they bring her into the center of tank plants, where she lays eggs and they are fertilized.

The eggs are very small and they are scattered in large numbers in many different directions; they stick to tank plants and spill on the tank bottom. This game is repeated several times. Each time the Buenos Aires tetra female lays eggs she and the males eat the eggs, but there are so many of them, that still about several hundreds of eggs are left.

After the Buenos Aires tetra spawns several times, you should remove both of them from the tank and put them into different volumes, so the female can rest.

In 2-3 days small juveniles hatch from the eggs and they hang of tank plants and walls. During this time you should feed them with infusorian or live small microorganisms and sufficiently aerate the tank water.

On the second day of their life the juveniles start swimming in schools and stay where there is a lot of food and eat it. They grow very fast and on the 8-10th day of their life they eagerly feed on cyclops. Next year the juveniles become reproductive.

In 10-15 day you can repeat the spawning with the same female, but it’s better to put some other male. During the second spawning there are usually less eggs.