Buenos aires tetra - Hyphessobrycon anisitsi

Scientific name: Hyphessobrycon anisitsi

Common name: Buenos aires tetra

Family: Characidae

Usual size in fish tanks: 5 - 6 cm (1.97 - 2.36 inch)

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Recommended pH range: 6 - 7.5

Recommended water hardness: 2 - 12°N (35.71 - 214.29ppm)

0°C 32°F30°C 86°F

Recommended temperature range: 20 - 26 °C (68 - 78.8°F)

The way how these fish reproduce: Spawning

Where the species comes from: South America

Temperament to its own species: peaceful

Temperament toward other fish species: peaceful

Usual place in the tank: Middle levels

General Information

The Buenos Aires tetra (Hyphessobrycon / Psalidodon anisitsi) is a hardy, fast-swimming characin native to the Río de la Plata basin—widely distributed in the Paraná/Paraguay systems and the Uruguay watershed across Argentina, Paraguay, Uruguay and southeastern Brazil. Adults typically reach 5–6 cm and form tight, lively schools. (Some modern sources place the species in the genus Psalidodon.)

Food & Feeding

Omnivorous: takes worms, insects, small crustaceans and plant matter. Use quality flakes or small sinking pellets as staple, and rotate frozen/live foods (baby brine shrimp, daphnia, cyclops, finely chopped bloodworms). Include vegetable content (spirulina, blanched greens) to satisfy grazing tendencies and help reduce plant-nipping. Feed small portions 1–2× daily.

Sexing

Differences are subtle: females are deeper-bodied (plumper when gravid), while males are slimmer; color is otherwise similar.

Breeding

An egg-scattering tetra with no parental care. Use a separate dim tank with fine plants/spawning mops or marbles; remove adults post-spawn. In captivity the eggs usually hatch in ~20–24 hours, and fry are free-swimming a few days later. Start with infusoria/liquid fry food, then Artemia nauplii.

Lifespan

Commonly 5–7 years with good maintenance; they’re considered among the hardiest small tetras.

Tank Requirements & Water Parameters

Tank size: long tank of 80–90 cm (32–36″) minimum for a shoal; larger is better for adults.
Water: tolerant and adaptable; aim for pH ~6.0–7.5, hardness ~2–12 °dH, temperature 20–26 °C (tolerates 18–28 °C). Cooler end often yields calmer behavior and longer lifespan.
Filtration & flow: clean, well-oxygenated water with moderate flow; regular sizeable water changes keep them in peak condition.
Aquascape: open mid-water lanes plus robust plants and hardscape. Because they nip soft plants, favor tougher species or plant-protected layouts.

Compatibility & Temperament

Boisterous shoaler—can be nippy. Keep in groups of 8–10 to diffuse aggression. Choose robust, fast tank mates (larger tetras/rasboras, barbs, rainbows, sturdy catfishes). Avoid long-finned, slow, or tiny species that may be harassed.

Behaviour & Usual Place in the Tank

Active mid-water schooling fish; they dash into cover when startled but spend most time in the middle of the column.

Short Description

Buenos Aires tetras are hardy, lively characins from the La Plata basin. Keep them in sizable shoals, provide open swimming space, robust plants, and a mixed omnivorous diet. Expect occasional plant-nipping and a confident, energetic presence in community aquaria.

Q&A

Where are they from? Widespread in the Río de la Plata basin: Argentina, Paraguay, Uruguay, and SE Brazil.
Are they plant-safe? Not really—known plant-nippers; use tough plants or plan for grazing.
How many should I keep? At least 8–10 to reduce nipping and establish a stable hierarchy.
Breeding time? Eggs typically hatch in ~20–24 h at typical aquarium temps; fry free-swim after a few days.