Red-tail barracuda - Acestrorhynchus altus

Scientific name: Acestrorhynchus altus

Common name: Red-tail barracuda

Family: Acestrorhynchidae

Usual size in fish tanks: 20 - 24 cm (7.87 - 9.45 inch)

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Recommended pH range: 5.5 - 7.1

Recommended water hardness: 7 - 16°N (125 - 285.71ppm)

0°C 32°F30°C 86°F

Recommended temperature range: 22 - 27 °C (71.6 - 80.6°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: aggressive to smaller

Usual place in the tank: Middle levels

Short description

The Red-tail barracuda (Acestrorhynchus altus) is a sleek, torpedo-shaped South American characin built for fast mid-to-upper-water strikes. It’s a nervous, highly alert predator that needs a long aquarium with open lanes for sprint bursts and unobstructed turns. Best kept singly or in very large tanks with equally robust tank mates that are too large to swallow.

Origin

South America; native to the Amazon and Orinoco drainages. Typically inhabits main channels and floodplain lakes, cruising open water near the surface.

Food and feeding

An obligate fish-eater in nature. In aquaria, train onto safer prepared foods: thawed fish strips (e.g., silversides), prawn/shrimp pieces, squid, and high-quality carnivore sticks offered with feeding tongs. Avoid feeder fish due to parasites/poor nutrition; use only as a last resort while weaning. Offer moderate portions once daily and promptly remove leftovers.

Sexing

No reliable external differences are known; adult females may appear slightly fuller when gravid.

Breeding

Home-aquarium breeding is undocumented. In the wild, this species is presumed to be an egg-scattering spawner like other acestrorhynchids, with seasonal cues and extensive space requirements.

Lifespan

Typically 8–10 years with excellent water quality and an appropriate, low-stress setup.

Behavior & compatibility

Skittish and reactive; may dash when startled. Generally ignores tank mates that are too large to be eaten, but will prey on smaller fish. Conspecific tolerance is variable—can be nippy or dominant in confined quarters. If attempted, keep a small group only in very large, long tanks with visual breaks; otherwise keep singly.

Tank requirements

• Tank size: prioritize footprint/length; substantially larger than 50 gal is recommended for adults (long tanks > 150 cm).
• Aquascape: open mid/upper-water lanes; use rock/wood at the sides/back to create sightline breaks without obstructing sprints.
• Cover: tight-fitting lid—this species is jump-prone when startled.
• Water: soft, clean, well-oxygenated; pH 5.5–7.1 is fine; many keepers succeed slightly above neutral if stable.
• Temperature: Adults often do well at 24–27 °C with steady conditions.
• Filtration/flow: high turnover and strong aeration; low nitrate via regular large water changes.

Pictures

Bought by aqua-fish.net from jjphoto.dk.