Marble Hatchetfish

Carnegiella strigata

Also known as: Marbled hatchetfish, Hatchetfish

Water Parameters

• Temperature: 24–28°C
• pH: 5.5–7
• Hardness (GH): 18–143 ppm (1–8 dGH)

Values above are general hardness (GH). For carbonate hardness (KH), the buffer that keeps pH stable, see the water parameters guide.

Care Summary

A living oddity that looks exactly like its name: a tiny fish with a deep, sharp, hatchet-shaped keel of a belly and a flat top, marbled in brown and cream, that spends its life pressed against the water's surface. Marble hatchetfish are the hobby's premier jumpers, equipped with enlarged pectoral muscles that let them skitter and even briefly fly across the surface, an escape behaviour that makes an absolutely sealed lid non-negotiable. Beyond that they ask for soft, warm, gently-moving blackwater conditions, small floating or surface foods to suit their upturned mouth, the security of a school, and a mature, planted tank, as most are wild-caught and dislike new setups. Kept well in a calm soft-water community with mid- and lower-level tankmates, a tight shoal of hatchets hanging beneath the surface adds a layer of life to a part of the tank most fish ignore. A characterful specialist rather than a beginner's first fish.

Tankmates

A peaceful, strictly surface-dwelling schooling fish that hangs motionless just beneath the waterline, so its compatibility hinges on the surface zone: avoid other surface-feeders such as gouramis and bettas that would compete or harass it, and avoid anything large enough to eat a 4cm fish. The best tankmates occupy the middle and lower water and are equally peaceful: small tetras, rasboras, corydoras, and otocinclus, plus dwarf shrimp, with which it is safe. Keep it in a group of at least six. The single most important husbandry point is a tight-fitting lid with no gaps, because hatchetfish are the most accomplished jumpers in the hobby and will launch themselves clean out of an open tank when startled (in the wild they leap from the water to escape predators and catch insects). Soft, gently-flowing water and floating plants for cover suit them best.

Compatible with

• Neon Tetra
• Cardinal Tetra
• Rummynose Tetra
• Harlequin Rasbora
• Bronze Corydoras
• Otocinclus
• Cherry Shrimp

Avoid keeping with

• Betta
• Dwarf Gourami
• Angelfish
• Large Cichlids
• Fin Nippers

Common Problems

• jumping from any gap in the lid
• sensitivity as wild-caught fish in new tanks
• poor health in hard, alkaline water
• preference for small surface foods

Sources: seriouslyfish.com, fishbase.org · Last updated: 2026-06-20