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 Furry Diary remembers it for you
A typical home-care rhythm for a Marbled Hatchetfish. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- 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
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.
- 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.