One of the easiest fish to keep, the Buenos Aires Tetra is great for the beginning aquarist!

Buenos Aires Tetras Hyphessobrycon anisitsi are hardy, long-lived, and prolific breeders. These handsome, full-bodied fish can reach up to about 2 3/4 inches (7 cm) in length and have a lifespan of about 5 to 6 years.

This fish has a pretty, silvery color overall, with some flashy neon highlights. Its most distinguishing feature is the bold, black ‘cross’ shaped pattern at the base of the tail fin, accented with red above and below.

These fish are great for beginners. They can adapt to most water conditions, within reason, and have no special requirements or considerations. A fairly peaceful fish, they will do very well in a community tank, but they do have a big appetite and must be kept well-fed. If they get hungry, they will nip the fins on any of their long-finned tankmates!  They are best kept in large groups of 5 or more individuals. Keeping them a good-sized school will also cut down on their desire to nip.

For many years, they were one of the most popular fish in the aquarium hobby. The Buenos Aires Tetra, however, will eat live plants. With so many people today growing plants in their aquariums, these fish have fallen a bit out of favor. If you are keeping an aquarium with artificial plants, they make a wonderful addition to a community tank.

For Information on keeping freshwater fish, see:
Freshwater Aquarium Guide: Aquarium Setup and Care

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Characiformes
  • Family: Characidae
  • Genus: Hyphessobrycon
  • Species: anisitsi
Buenos Aires Tetra – Quick Aquarium Care
  • Aquarist Experience Level: Beginner
  • Size of fish – inches: 2.8 inches (6.99 cm)
  • Minimum Tank Size: 25 gal (95 L)
  • Temperament: Semi-aggressive
  • Aquarium Hardiness: Moderately hardy
  • Temperature: 64.0 to 82.0° F (17.8 to 27.8&deg C)
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Habitat: Distribution / Background

The Buenos Aires Tetra Hyphessobrycon anisitsi (previously Hemigrammus caudovittatus and Hemigrammus anisitsi) was described by Eigenmann in 1907. The species is not listed on the IUCN Red List. They are found in South America in the La Plata region, Argentina, Paraguay and southeastern Brazil.

These schooling fish inhabit a range of biotypes, including streams, rivers, lakes, and ponds. In nature, these tetras feed on worms, crustaceans, insects, and plants.

  • Scientific Name: Hyphessobrycon anisitsi
  • Social Grouping: Groups – .
  • IUCN Red List: NE – Not Evaluated or not listed


The Buenos Aires Tetra is a full-bodied, large fish that can reach up to 2.75 inches (7 cm) and have a lifespan of 5 to 6 years. Its silvery color picks up flashy neon highlights. The top and bottom of the tail fin is generally red, as are the pelvic and anal fins. The dorsal fin also has a hint of red. Its most distinguishing characteristic is the caudal peduncle, which features a bold, black ‘cross’ shape.

  • Size of fish – inches: 2.8 inches (6.99 cm)
  • Lifespan: 6 years – They have a lifespan of about 5 to 6 years.

Fish Keeping Difficulty

The Buenos Aires Tetra is a hardy fish that is good for the beginning fish keeper. They are very durable and long-lived, and do not have any special needs or requirements that have to be met for them to thrive. However, they are hearty feeders that must be kept well-fed or they may resort to nipping at their long-finned companions. Keeping them in a school will help reduce fin-nipping. They will also eat live aquarium plants.

  • Aquarium Hardiness: Moderately hardy
  • Aquarist Experience Level: Beginner

Foods and Feeding

The Buenos Aires Tetras are omnivorous. In the wild they primarily feed on worms, crustaceans, insects, and plants, but in the aquarium they will generally eat all kinds of live, fresh, and flake foods. To keep a good balance, give them a high quality flake food every day. To keep these tetras at their best and most colorful, offer regular meals of live and frozen foods, such as bloodworms, daphnia, and brine shrimp. Vegetables should also be added to their diet. Blanched spinach is a great choice. Feed these tetras several times a day and only what they can consume in 3 minutes or less at each feeding.

  • Diet Type: Omnivore
  • Flake Food: Yes
  • Tablet / Pellet: Yes
  • Live foods (fishes, shrimps, worms): Some of Diet
  • Vegetable Food: Some of Diet – This fish loves to eat aquarium plants.
  • Meaty Food: Some of Diet
  • Feeding Frequency: Several feedings per day

Aquarium Care

Buenos Aires Tetras are not exceptionally difficult to care for, provided their water is kept clean. Aquariums are closed systems and regardless of size, all need some maintenance. With home aquariums, the nitrates and phosphates build up over time, and water hardness increases due to evaporation. To combat these ever-changing conditions, water should be replaced on a regular basis. At least 25 to 50% of the tank water should be replaced every other week, especially if the tank is densely stocked.

  • Water Changes: Bi-weekly

Aquarium Setup

This fish is a very active swimmer and needs plenty of open space. It also likes to be kept in a school with 5 or more companions of its own kind. Keep Buenos Aires Tetras in a tank at least 20 inches long and ideally 25 or more gallons to provide them with plenty of space for swimming and shoaling.

They are happy with any type of substrate and do fine with normal aquarium lighting. However, the tank should be securely covered as these fish are skilled jumpers and will probably do so if given the opportunity. This is a very undemanding species, as can be seen by the wide range of acceptable conditions. However they will eat most plants with the possible exception of Java Fern. Thus, the tank should mostly be decorated with driftwood, rocks, and plastic plants.

  • Minimum Tank Size: 25 gal (95 L) – This fish is very active and requires space and companions of its own kind so it can school.
  • Suitable for Nano Tank: Yes
  • Substrate Type: Any
  • Lighting Needs: Moderate – normal lighting
  • Temperature: 64.0 to 82.0° F (17.8 to 27.8&deg C)
  • Breeding Temperature: 75.0° F – These fish will spawn at 75° F (24° C).
  • Range ph: 6.0-8.0
  • Hardness Range: 2 – 30 dGH
  • Brackish: No
  • Water Movement: Strong
  • Water Region: All – These fish will swim in all areas of the aquarium.

Social Behaviors

The Buenos Aires Tetra are generally a good community fish. They are quite active and will school when provided with plenty of space. These tetras are best kept with their own kind in a school of 5 or more or with other fish that can tolerate their boisterous behavior. Just remember to keep them well fed, so they don’t snack on the fins of their tankmates. Sometimes, they can be outright aggressive, so monitor them in community tanks. To avoid fin nipping, keeping this fish in schools of 5 or more will restrict most of the aggression to within the school.

Good tankmates are similiarly sized tetras, rainbowfish, larger rasboras, barbs, and danionins. Non-aggressive cichlids also do well with these tetras. Slow-moving, long-finned fish like gouramis, anabantoids, and dwarf cichlids will nip and harrass this tetra, so they do not make good tankmates.

  • Venomous: No
  • Temperament: Semi-aggressive – Although not usually aggressive, this fish is very active and will irritate more temperate fish. It is also a notorious fin nipper, so select tankmates carefully.
  • Compatible with:
    • Same species – conspecifics: Yes – Best kept in a school of 5 or more.
    • Peaceful fish (): Monitor – Watch for fin nipping induced stress in other fish. Sometimes Buenos Aires Tetras can be outright aggressive, especially if not kept in a school.
    • Semi-Aggressive (): Threat
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • Monitor – Tetras can out compete them for food.
    • Shrimps, Crabs, Snails: Safe – not aggressive
    • Plants: Threat – One of the only drawbacks to this fish is that it will eat plants.

Sex: Sexual differences

The males have brighter, red fins, sometimes tending towards yellow. The female is fuller-bodied with a more rounded stomach.

Breeding / Reproduction

Buenos Aires Tetras have been bred in captivity. These egg scattering spawners exhibit no parental care, but they are easy to breed, which makes them ideal candidates for the beginning aquarist interested in a breeding project. Adults in good condition will spawn in a mature community tank, but the eggs and fry will most often be eaten. To get the best mortality rate for the fry, the aquarist must use a separate breeding tank.

The breeding tank should be well-planted and around 10 or 20 gallons. Keep the tank dimly lit with clumps of spawning mops or java moss, so the female has a place to deposit the eggs. A layer of mesh also works if it is wide enough for eggs to pass through but small enough to keep parents out. The water should be soft and slightly acidic to neutral with a pH of 6.5 to 7.2 and a temperature of 75° F (24° C). A small, air-powered sponge filter is needed for gentle filtration and water movement.

These fish can be bred as a pair or in a small group consisting of either an equal number of males and females or 1 to 2 males with several females. Prior to spawning, condition the breeders with a good supply of small, live foods. After a few days, select a breeding pair or small group and transfer them into the breeding tank in the evening. A mature female’s belly will become nicely rounded when she is full of eggs. Choose males that are the most colorful.

They will usually begin to spawn at dawn. Females may lay as many as 2000 egg during this time, depositing them on the plants or green floss. The parents should be removed immediately after spawning, or they will eat the eggs. The eggs will begin to hatch in 24 to 36 hours, and the fry will be free-swimming in another 3 to 4 days. For the first few days, feed the fry infusoria-type foods until they can feed on microworm or brine shrimp nauplii. See Breeding Freshwater Fish: Characins for a general description of breeding processes, and see Fish Food for Fry for information about types of foods for raising the young.

  • Ease of Breeding: Easy

Fish Diseases

As with most fish, Buenos Aires Tetra are prone to skin flukes, parasitic infestations (protozoa, worms, etc.), ichthyobodo infection, parasitic infestations (protozoa, worms, etc.), bacterial infections (general), and bacterial disease. Buenos Aires Tetra are extremely hardy and disease is not usually a problem in a well-maintained aquarium. That being said, there is no guarantee that you won’t have to deal with health problems or disease. Remember that anything you add to your tank can introduce disease. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so as not to upset the balance.

A good thing about Buenos Aires Tetra is that due to their resilience, an outbreak of disease can often be limited to just one or a few fishes if dealt with at an early stage. When keeping more sensitive types of fish, it is common for all fishes to be infected even before the first warning signs can be noticed. The best way to proactively prevent disease is to give your Buenos Aires Tetra the proper environment and a well-balanced diet.

The more closely their environment resembles their natural habitat, the less stress the fish will have, making them healthier and happier. It is recommended to read up on the common tank diseases. Knowing the signs of common tank diseases and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.


The Buenos Aires Tetra is reasonably priced and readily available both in fish stores and online.