At a glance the quick version
Looks how to spot one
Small, deep-keeled, scaled characin
A tiny fish with a flat back and a deep, rounded chest that gives it a hatchet-like side view. The body is a silvery gold with a pale line from head to tail and dark brown marbling in slanted bands across the lower half. Females tend to grow a little larger and fuller in the belly.132
Personality what they are like
A calm, gentle fish that spends its time in a group just under the surface. It leaves other fish and even fry alone, which makes it a good companion for dwarf cichlids, though its small size means tankmates should be equally mild.13
Daily activity how busy a day looks
Lives and feeds right at the top of the water column, so it needs open surface area. It can leap when startled, so a well-fitted lid is recommended.123
Grooming and care the hands-on bits
Prefers soft, acidic, tea-stained water kept clean and stable. Suggested ranges: about 20-28 C (FishBase gives 24-28 C), pH 4.0-7.0 (FishBase gives 5.0-8.0), hardness 1-10 dGH. Keep a tight cover on the tank.12
Home where they are happiest
Tank of at least 75-80 cm length (around 68 litres) with floating plants or overhanging cover, gentle flow, and leaf litter or wood to recreate a blackwater stream.12
Food basics what goes in the bowl
Feeds mainly on small insects and crustaceans taken at the surface. Floating dried foods are accepted, ideally alongside small live or frozen foods such as brine shrimp, daphnia and small worms, and the odd small fruit fly.123
Company who they like around
A schooling fish that feels most secure and confident in a group; at least 5 is the minimum, with 10 or more ideal.12
The story where it all began
Named by Albert Guenther in 1864, this fish has long been a familiar sight in the aquarium hobby. Nearly all fish sold are collected from the wild, mostly in Brazil, and genetic work from 2012 hints that the Rio Negro fish may actually be two separate species.13
Fun facts for the dinner table
- 1
The genus name honours Margaret Carnegie, daughter of the industrialist Andrew Carnegie.3
- 2
Two pattern forms are known, one with V-shaped markings and one with Y-shaped markings.3
- 3
At about 25 C its eggs hatch in roughly 36 hours.2
- 4
In the rainy season the fish travel upstream into flooded forest to feed and spawn.3
Recognised by the official bits
- IUCN Red List
- Least Concern (assessed October 2020)2
- FishBase
- Described by Guenther in 18642
The care rhythm a typical week and year
A typical home-care rhythm for a Marbled Hatchetfish. A starting point, not a vet's advice.
- FeedingSmall amounts once or twice a dayevery day
- Temperature checkevery day
- Water changeAbout 25% of the waterevery week
- Water testevery week
- Glass cleanevery week
- Filter rinseRinse in old tank water, never tap waterevery month
Owner questions the things everyone asks
How often should I feed my Marbled Hatchetfish?
Furry Diary's starting plan is to offer small amounts once or twice a day. These fish feed at the surface, so use floating foods and watch that they eat everything within a couple of minutes.12 Pet Wiki plan
What does a Marbled Hatchetfish eat, and what should it never eat?
They eat small insects and crustaceans at the surface, and accept floating dried foods along with live or frozen brine shrimp, daphnia, and small worms. Never feed large sinking pellets or anything that could cause bloating; stick to tiny surface foods.123
How much space does a Marbled Hatchetfish need?
A tank of at least 75-80 cm length (around 68 litres) is recommended. They need open surface area for swimming and floating plants for cover.12
What temperature, light or water does a Marbled Hatchetfish need?
They prefer soft, acidic, tea-stained water with a temperature of 20-28°C, pH 4.0-7.0, and hardness 1-10 dGH. Gentle flow and dim lighting with floating plants suit them best.12
How often should I clean a Marbled Hatchetfish's home?
Furry Diary's plan suggests a weekly 25% water change, weekly glass cleaning, and a monthly filter rinse in old tank water. Always test water weekly to keep conditions stable. Pet Wiki plan
Can a Marbled Hatchetfish live with others?
Yes, they are calm and gentle, and do well in a school of at least 5 (10 or more is ideal). They are good companions for dwarf cichlids and other mild fish, but avoid large or aggressive tankmates.123
How long does a Marbled Hatchetfish live?
Their lifespan varies depending on care, but with stable water and good diet they can live several years. For exact numbers, ask a good breeder or an exotic-pet vet.
Can I handle a Marbled Hatchetfish?
No, they are delicate and can leap when startled. Always use a net and avoid handling them with your hands; keep a tight lid on the tank.123
Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.
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Common HatchetfishWhere this comes from
Every fact on this page has a numbered source. Spotted an error? support@petwiki.app.
- Carnegiella strigata - Seriously Fish seriouslyfish.comused for origin, size, care, diet, behaviour, history
- Carnegiella strigata summary - FishBase fishbase.seused for size, water parameters, IUCN, reproduction
- Marbled hatchetfish - Wikipedia en.wikipedia.orgused for appearance, etymology, behaviour, fun facts
Checked 2026-09-30. Text is written in our own words from these sources.