Pygmy Hatchetfish Care Guide: Surface Dwellers That Fly

The pygmy hatchetfish (Carnegiella myersi) is one of the smallest and most fascinating freshwater fish available. At just 2–2.5 cm, this surface-dwelling oddity has a deep, keeled body shaped like a tiny axe head — and it can actually leap from the water using powerful pectoral muscles, the only true flying fish in freshwater. This pygmy hatchetfish care guide from Gensou Aquascaping at 5 Everton Park will help you keep these delicate but rewarding nano fish.

Pygmy Hatchetfish Overview

Pygmy hatchetfish are found in slow-moving blackwater streams and flooded forest areas in Peru, Bolivia and Brazil. Their transparent to silvery body with a faint dark lateral line provides camouflage when viewed from below against the bright water surface. They are strict surface dwellers that rarely venture below the top 5 cm of the water column. With proper care, they live for two to three years.

Tank Requirements

A school of eight to twelve pygmy hatchetfish needs at least a 40-litre tank with a large surface area. A long, shallow tank is ideal — depth matters less than surface space. A tight-fitting lid is absolutely essential. These fish will jump through the smallest gap, especially when startled. Maintain the temperature between 24 °C and 28 °C, pH 5.0–7.0 and GH 2–10 dGH. They strongly prefer soft, acidic water enriched with tannins.

Creating the Right Environment

Floating plants are critical — they provide shade, resting spots and a sense of security. Use Salvinia, Amazon Frogbit or Red Root Floaters to cover 50–70 per cent of the surface. Tannin-stained water from catappa leaves or driftwood mimics their natural blackwater habitat and noticeably reduces stress. Low to moderate lighting suits them best. Keep water flow gentle — strong currents exhaust these tiny fish.

Diet and Feeding

Pygmy hatchetfish feed exclusively at the surface. They eat tiny insects, mosquito larvae and microorganisms in the wild. In captivity, offer crushed flake that floats, freeze-dried cyclops, frozen daphnia and baby brine shrimp. Live fruit flies (wingless Drosophila) are the ultimate treat and trigger exciting feeding behaviour. Sinking foods are useless — these fish will not dive to retrieve them. Feed small amounts three times daily.

Tank Mates

Choose small, peaceful species that occupy the mid-water and bottom zones. Excellent companions include ember tetras, green neon tetras, pencilfish, pygmy Corydoras, otocinclus and dwarf shrimp. Avoid any fish large or aggressive enough to threaten them, surface-feeding competitors, and species that create strong water movement. A biotope tank with other South American nano species creates a stunning and natural display.

Breeding Pygmy Hatchetfish

Breeding in captivity is difficult and rarely achieved. They scatter eggs among floating plant roots, and the tiny fry require extremely small first foods like paramecium. Very soft, acidic water with pH below 6.0 and minimal lighting seem to encourage spawning. The challenge lies in raising the microscopic fry rather than triggering spawning itself.

Common Health Issues

Pygmy hatchetfish are sensitive to water quality fluctuations and stress. They are prone to ich, especially after transport, and bacterial infections in hard or alkaline water. Acclimate them very slowly using the drip method over two to three hours. Once established in stable conditions, they become more resilient. The biggest killer is jumping — ensure every possible escape route is blocked.

Related Reading

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• Pygmy Corydoras Tank Mates: Tiny Bottom Dwellers Need Gentle Friends
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