The Peaceful Buenos Aires Tetra

Buenos Aires Tera, Tropical Freshwater Fish
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The Buenos Aires Tetra derives its name from the capital of Argentina, Buenos Aires. The city sits on the western shore of the Río de la Plata, located along the southeastern coastline of South America. Considered a river by some and a gulf by others, the Río de la Plata is formed by the joining of the Paraná and Uruguay Rivers, which are also home to the Buenos Aires Tetra.

The Buenos Aires Tetra has been imported for a number of years and became extremely popular due to its hardiness and ease of care.

Specimens now offered for sale are all captive bred, primarily from commercial fish farms in Florida. They were once sold in large numbers, but due to their propensity for eating plants, they have become less popular over the years.

The fish is now known by the scientific name of Hyphessobrycon anisitsi, but the Buenos Aires Tetra has also been referred to as Hemigrammus anisitsi, Hemigrammus caudovittatus, and Hyphessobrycon erythrurus. However, reclassification of all species in these genera is expected.

Buenos Aires Tetra: Overview

  • Scientific Name: Hyphessobrycon anisitsi
  • Synonym: Hemigrammus anisitsi, Hemigrammus caudovittatus, Hyphessobrycon erythrurus
  • Common Name: Buenos Aires Tetra, Diamond Spot Characin, Red Cross Fish
  • Family: Characidae
  • Origin: Argentina, southeastern Brazil, Paraguay
  • Adult Size: 2.75 inches (7 cm)
  • Social: Peaceful shoaling fish
  • Lifespan: 5 years
  • Tank Level: Mid-level
  • Minimum Tank Size: 29 gallons
  • Diet: Omnivore, accepts all foods
  • Breeding: Egg-scatterer
  • Care: Easy
  • pH: 5.8-8.5
  • Hardness: to 35 dGH
  • Temperature: 64-82 F (18-28 C)


The Buenos Aires can grow to nearly 3 inches in size and it is one of the larger Tetras. The body is silvery with a narrow blue line that starts behind the gill and ends at the caudal (tail) fin, where there is a black diamond shaped spot.

The fins are orange-red and a splash of red can be seen at the top of the eye. Several color variations have been bred, including one that has a yellow tail as well as an albino variety.


Although Tetras are generally peaceful, avoid keeping them with small fish such as the Neon Tetra as well as long finned fish such as the Betta and Angelfish.

The Buenos Aires Tetra does well with larger sized tetras, such as the Black Widow or Serpae Tetra, as well as with Barbs, Danios, Gouramis, and Rainbowfish. Bottom dwelling fish are also good companions. You can also use a school of Buenos Aires Tetras as dither fish in a tank of non-aggressive cichlids.


The undemanding Buenos Aires Tetra is adaptable to a range of aquarium conditions. Water temperatures can range from the mid-60s to 80 degrees, making it suitable for heated as well as unheated tanks. It's a highly active fish and it does require a sizable open swimming space. Longer tanks are ideal.

The Buenos Aires Tetra is not suitable for most live planted tanks as it's known to devour them. Use artificial plants instead or select sturdy live plants such as Anubias, Java Fern or Vallisneria. Round out the décor with driftwood and rocks around the periphery of the tank, and your Buenos Aires Tetras will be quite at home.


The Buenos Aires Tetra will accept a wide variety of foods. Provide this fish with some lettuce, spinach or other vegetation to munch on, given its propensity for eating live plants. In lieu of fresh vegetation, provide a good quality spirulina flake food. Flake, dried, and freeze dried foods add well-needed variety to their diet and will be readily accepted. They are also quite fond of live foods such as bloodworms, daphnia and mosquito larvae.

Sexual Differences

Males have brighter red fins and are generally more colorful overall, particularly during spawning. Females are larger and broader with a rounder belly.


Buenos Aires Tetras are easy to breed; they are egg scattering fish that can be spawned in pairs or in groups. If spawned in a group, use the approximately the same number of males as females.

Condition spawning fish with live foods prior to spawning attempts.

The adults will eat the eggs and young, so use a separate breeding tank. Provide sturdy plants such as Java Moss or spawning mops for the fish so scatter their adhesive eggs on. Keep the water slightly acidic and the water temperature at 75 F. Gentle filtration, such a sponge filter is recommended.

Remove the adults once the eggs have been laid. The eggs will hatch in approximately 24 hours. In three to four days the fry will have consumed their egg sacks and will be free swimming. Initially, feed the fry infusoria or commercially prepared fry food such as liquifry. As they grow larger, feed them freshly hatched brine shrimp, micro worms, or finely ground high-quality flake food or fry food.