Diamond Tetra (Moenkhausia pittieri)

Moenkhausia pittieri, the Diamond Tetra, is a medium-sized tetra from the coastal rivers of Venezuela, particularly associated with Lake Valencia and surrounding drainages. Despite its extraordinary iridescent beauty, it is somewhat underappreciated in the aquarium hobby compared to more commercially marketed species — a situation that seems inexplicable once the fish is seen under good aquarium lighting.

The common name captures the species perfectly: every scale on the body reflects light independently, creating a scintillating, diamond-like sparkle across the entire fish. The effect is most dramatic under moderate to bright lighting — the fish appears to shift from silver to gold to green to violet as light angle changes. Males develop long, flowing dorsal fin rays that contribute further to the spectacular visual presentation.

Diamond Tetras grow to approximately 6 cm, making them a medium-sized tetra suitable for aquariums of 80 litres or more. They are peaceful schooling fish compatible with a wide range of community species. The purple to violet iridescent sheen in the scales and fins is particularly vivid in soft, slightly acidic water, which also enhances the diamond-like scale reflection.

In groups of eight or more in a well-lit planted aquarium, Diamond Tetras create one of the most dazzling small-fish displays available — the coordinated movement of the school produces a constantly shifting, scintillating effect.

Tank Setup: A minimum 80-litre planted aquarium for a school of eight. Open mid-water swimming space with planted edges and background. Moderate to bright lighting enhances the diamond reflection effect. Good filtration with moderate water flow. A tight lid — active swimmers.

Water Parameters: Temperature 23–28°C; pH 5.5–7.5; GH 3–12 °dH; KH 1–6 °dH. Prefers moderately soft, slightly acidic water for best colour expression. Tolerates a range of conditions.

Feeding: Omnivore. Accepts quality flake, micro pellets, frozen bloodworm, brine shrimp, and Daphnia. Feed twice daily. Medium-sized mouths accept standard community foods.

Tank Mates: Compatible with virtually all peaceful community species: other tetras, rasboras, corydoras, gouramis, loaches, livebearers, and small cichlids. Avoid aggressive fish and very small nano fish.

Behaviour: Peaceful schooling fish. Groups of 10+ produce the most impressive diamond-shimmer schooling display. Males develop elaborate dorsal fins with age. Non-aggressive toward any tank mate.

Health: Hardy and long-lived. Sensitive to elevated nitrates (above 20 ppm) — weekly 25% water changes essential. Susceptible to ich during temperature drops. Generally disease-resistant in well-maintained conditions.