Silver Hatchetfish

Silver Hatchetfish (Gasteropelecus sternicla) is a remarkable freshwater fish with one of the most extraordinary body shapes in the aquarium hobby. The enormously enlarged, keel-shaped chest — formed by massive pectoral muscles that account for up to a quarter of the fish's total body weight — powers genuine flight above the water surface to escape predators. The Silver Hatchetfish is the classic and most commonly encountered medium-sized hatchetfish — a clean silver body with a dark horizontal midline stripe running from the gill cover to the tail. At 2–2.5 inches it is notably more substantial than the Carnegiella species while retaining the same extraordinary deep-keel body profile. Gasteropelecus — medium-sized, more robust than Carnegiella.

Feeding & Care Tip: Sera Vipan Tropical Flakes and Hikari Micro Pellets make excellent surface staples. Supplement 2–3× per week with Hikari Frozen or Freeze-Dried Baby Brine Shrimp fed at the surface and Hikari Frozen Daphnia. Feed small amounts at the surface — these are strict surface feeders.

⚠ Tight-Fitting Lid Essential: Hatchetfish are genuine fliers — the enormous pectoral muscles that give them their deep keel-shaped chest power actual leaps out of the water to escape predators. This is not a tendency to jump; it is a physical ability unique among freshwater fish. Any gap in the lid will result in fish on the floor. A fully sealed lid with only the minimum opening for equipment is required.

Native to slow-moving rivers and streams across the Amazon basin — more adaptable to varied water conditions than the smaller Carnegiella species, though soft, slightly acidic to neutral water produces the best long-term results. Good surface cover from floating plants, gentle filtration, and stable water quality are important.

Keep in groups of at least six. More robust than the Carnegiella hatchetfish — a good choice for aquarists who want the hatchetfish experience with a somewhat more forgiving fish. Same strict surface-feeding behavior and jumping ability. Compatible with most peaceful community fish that inhabit lower water zones.

Hatchetfish are strict surface feeders — they will not descend to take food from the mid-water or substrate. All food must be offered at the surface or just below it. Floating flake food and pellets work well; frozen foods should be fed near the surface before they sink. Any food that sinks past the top few inches of the water column will not be eaten by the hatchetfish.

Care & Ideal Parameters