Roestes Sabretooth Tetra

Roestes molossus is a member of the Cynodontidae family — the same group that includes the Payara — and shares the family's characteristic enlarged, interlocking canine teeth adapted for seizing prey fish. It is a medium-to-large species reaching about 18 cm with a notably deep, robust body and a large, upward-angled mouth. It is found in the Amazon basin and is among the rarer large predatory characins available through specialist importers.

In the aquarium, Roestes molossus requires soft, warm water, excellent filtration, and a tank of at least 300 litres. It is an ambush predator that appreciates some cover in the form of driftwood or overhangs from which it can strike at prey. It will consume any fish it can fit in its large mouth and should be housed only with fish considerably larger than itself or as a solitary specimen.

Feeding should initially consist of live or fresh whole fish, with gradual weaning onto large frozen fish and eventually carnivore pellets. Its impressive fanged morphology, deep body, and rarity make it a highly sought-after specialist oddity for collectors of unusual predatory characins.

Water: Soft, pH 5.5–7.0, 24–28°C; good oxygenation and filtration; avoid sudden parameter changes. Tank: 300 L minimum; driftwood cover for ambush; no tankmates smaller than itself. Feeding: Piscivore — live or fresh whole fish; wean to frozen fish and carnivore pellets. Breeding: Not documented in captivity. Compatibility: Aggressive piscivore; solo or with very large non-swallowable species only.