Atraterío Dogtooth Tetra

Gilbertolus atratoensis is a small but remarkably specialised predatory characin from the Atrato River drainage of northwestern Colombia. Its distinctive upturned mouth and enlarged, fang-like teeth are adaptations for snatching insects from the water surface or striking at small fish from below — a unique hunting strategy among characins. It grows to only 12 cm but is a fierce, active predator that should not be underestimated by the species it can consume.

In the aquarium, Gilbertolus atratoensis does best in a species-specific or specialist blackwater setup of at least 200 litres, with soft, acidic water, tannin-stained conditions, and floating plants that help it feel secure at the surface. It is a surface and upper-water-column fish that hunts in the surface film and should be provided with a tightly fitting lid as it will jump readily.

This species is rarely available in the trade and represents a genuine specialist find for aquarists interested in unusual predatory characins and Colombian blackwater biotopes. Feeding on live or frozen invertebrates — crickets, mealworms, frozen bloodworm, and small live fish — is recommended. Its fascinating hunting posture and rarity make it a prized oddity.

Water: Soft, pH 5.0–7.0, 22–27°C; tannin-stained blackwater conditions ideal; no strong current. Tank: 200 L minimum; floating plants; surface coverage; very secure lid — active jumper. Feeding: Surface predator — live or frozen insects, bloodworm, small live fish; will not accept pellets easily. Breeding: Not documented; rare in trade. Compatibility: Aggressive toward fish it can swallow; best in species tank or with large peaceful companions.