Saber-tooth Tetra

Raphiodon vulpinus is a large, impressively armed predatory characin belonging to the family Cynodontidae. Its most striking features are the dramatically elongated, needle-like lower jaw teeth that protrude above the upper jaw when the mouth is closed — a more extreme version of the sabretooth morphology seen in the related Hydrolycus. It is a highly compressed, laterally flattened fish with a distinctly large, upturned mouth and silvery flanks with a strong iridescent sheen.

Native to the Amazon and Paraná river systems, Raphiodon vulpinus inhabits open-water mid-river habitats where it hunts fast-moving schooling fish. In the aquarium it requires a very large, well-oxygenated tank of at least 800 litres with strong flow and pristine water quality. It is an exceptionally fast, powerful swimmer that will stress easily in cramped conditions and is sensitive to poor water quality.

Feeding initially requires live fish, but patient weaning to fresh whole fish and frozen fish preparations is achievable with time. It is strictly a specialist fish for experienced aquarists or public aquarium collections. Its remarkable fang morphology and silver compressed body make it one of the most visually extraordinary large characins available to specialist collectors.

Water: Soft, pH 5.5–7.5, 24–28°C; very high oxygenation; strong current; clean conditions. Tank: 800 L minimum; open mid-water; minimal décor; tightly secured lid. Feeding: Piscivore — live fish initially; wean to fresh whole fish and large carnivore preparations. Breeding: Not documented in captivity. Compatibility: Apex piscivore; solo or with equally large non-swallowable species only.