Carnegiella strigata
True surface specialist, the keeled chest houses enlarged pectoral muscles that let them 'fly' over the water to escape predators. Tight lid is non-negotiable: any opening becomes an exit. Best in a heavily planted blackwater tank with floating plants for cover.
Marbled Hatchetfish (Carnegiella strigata) reaches 3.5–4.5 cm as an adult and needs a minimum tank of 75 L. Native to Amazon basin, Peru & Brazil, it lives in the top (strictly surface) water column with a peaceful temperament. Aim for 24–28 °C, pH 5.0–6.5, and 1–8 dGH hardness. Lifespan is 3–5 years with good care. Keep marbled hatchetfish in groups of 6+, yes schoolers need numbers to display natural behaviour. Diet: micropredator (insectivore), Floating micro pellets, flake, fruit flies, mosquito larvae. Will not feed off the bottom. Plant-safe: Yes. Shrimp-safe: Yes.
Care at a glance
True surface specialist, the keeled chest houses enlarged pectoral muscles that let them 'fly' over the water to escape predators. Tight lid is non-negotiable: any opening becomes an exit. Best in a heavily planted blackwater tank with floating plants for cover.
By Mike ElmiraUpdated 3 min read
Part of our complete guide to aquarium fish for the planted tank.
The parameters that decide whether marbled hatchetfish fits in your tank.
Top (strictly surface)
Yes
Group of 6+
Gasteropelecidae
Micropredator (insectivore)
Floating micro pellets, flake, fruit flies, mosquito larvae. Will not feed off the bottom.
3–5 yrs
Very hard
Surface of slow shaded Amazon tributaries
Amazon basin, Peru & Brazil
Tank-mate safety and the species this one is documented to thrive (or fail) alongside.
Anything peaceful that doesn't occupy the top water column: cardinals, rummynose tetras, corydoras, otocinclus, German blue rams. They essentially ignore mid- and bottom-level tank mates.
Aggressive surface feeders (gouramis can intimidate them), large predatory fish, anything that startles them into jumping.
Hard-won lessons from the tank.
Feed at the surface — sinking food is wasted. Sprinkle fruit flies, mosquito larvae, or floating micro pellets across the surface. A group of 6+ in a heavily planted blackwater tank with extensive floating cover is a niche but stunning specialty display. Lid security is the difference between a thriving colony and finding crispy fish on the floor.
Genus 'Carnegiella' honours Margaret Carnegie Miller, daughter of Andrew Carnegie and patron of natural history. Species 'strigata' = 'striped/grooved' for the marbled pattern.
What can go wrong and how to spot it.
Failure modes, in order of how dramatic the fix is.
Sensitive to ich and bacterial infections during shipping stress. Their thin scales make them vulnerable to scrapes from rough netting. Once acclimated to good water they're hardy.
Often described as 'flying fish' — they don't actually fly. They use enlarged pectoral muscles (the keeled chest is solid muscle, not air sacs) to vibrate the pectoral fins and propel themselves out of water in a short low arc to escape predators. They land within a metre.
The practical routine, read top to bottom.
75 L+ with the longest water surface area possible (low and wide is better than tall and narrow). Heavy floating plants — frogbit, dwarf water lettuce, salvinia. Tannins, soft acidic water (pH 5.5–6.5), gentle flow. TIGHT-FITTING LID with no gaps — they will jump through any opening, including filter inlets without covers.
4 weeks with absolute lid security. Watch for slow wasting — common in stressed shipped fish.
Where it comes from, how it behaves, and the variants you'll see at retail.
Where it lived before it came home.
Slow tributaries and floodplain pools of the Amazon basin, especially Peru and Brazil. Tannin-stained soft acidic blackwater with dense surface vegetation. They occupy the top 5 cm of the water column exclusively.
Almost exclusively surface insects and falling terrestrial invertebrates. Fruit flies, mosquito larvae, ants, beetles.
Not threatened. Mostly wild-caught from Amazon tributaries; captive breeding remains uncommon.
How they pair, reproduce, and grow.
Very difficult. Females may be marginally fuller-bodied. Most sexing requires breeding-condition observation.
Extremely rare in captivity. Egg scatterers among floating plant roots; eggs sink slowly. Soft very acidic water, dense floating mat (riccia, water sprite), absolute parameter stability. Most reports of successful breeding come from dedicated species-only tanks.
The named cultivars and the lookalikes worth flagging.
Wild type only. Often confused with silver hatchetfish (Gasteropelecus sternicla — larger and plainer) and pygmy hatchetfish (C. myersi — smaller, less common). Marbled hatchets have the most pronounced black-and-cream marbling pattern.
Direct answers to the questions search engines and AI assistants surface most often about this species.
Marbled Hatchetfish (Carnegiella strigata) needs a minimum tank of 75 L. They live in the top (strictly surface) water column and should be kept in groups of 6+, so a longer footprint matters more than depth.
Target 24–28 °C, pH 5.0–6.5, and 1–8 dGH hardness. Acclimate slowly when moving them between water sources.
Shrimp safety: Yes. Plant safety: Yes.
Marbled Hatchetfish are micropredator (insectivore). Floating micro pellets, flake, fruit flies, mosquito larvae. Will not feed off the bottom.
On Fin & Stem's 1–5 difficulty scale this species rates 3/5. Intermediate, stable parameters and a mature tank matter. Breeding difficulty: very hard.
Typical lifespan in a well-maintained tank is 3–5 years.
A planted tank is a system. Pair this fish with one entry from each other pillar to plan the whole scape.
