Marbled hatchetfish
A small South American freshwater fish kept in aquariums for its unique shape and surface-dwelling habits.
The marbled hatchetfish is a tiny ray-finned fish from the Gasteropelecidae family. It lives in blackwater streams across northern South America and is widely collected for the global aquarium trade.
- Maximum length is just 3.5 cm.
- Lives in blackwater streams with acidic conditions.
- Popular in the aquarium trade, mostly wild-caught.
- Eggs hatch in 36 hours at 25°C.
- Named after Margaret Carnegie by Carl H. Eigenmann.
What it is
This species belongs to the family Gasteropelecidae, which also includes the genera Gasteropelecus and Thoracocharax. The body is triangular and deep, measuring up to 3.5 centimetres in length. Its colouration features a golden-silver hue overlaid with a dark brown marbled pattern. A pale stripe extends from the head to the tail. The specific name refers to furrows or grooves, likely describing four dark bands radiating from the throat. Different populations show variations in body depth, fin ray counts, and colour patterns, leading to historical classifications of subspecies based on V-shaped or Y-shaped markings.
Where it lives
The fish inhabits northern South America, specifically within the Amazon and Orinoco drainage systems as well as coastal drainages in the Guianas. Recorded countries include Brazil, Bolivia, Peru, Ecuador, Colombia, Venezuela, Guyana, Suriname, and French Guiana. It appears restricted to blackwater environments. In the Rio Negro drainage, it thrives in habitats with dense overhanging riverside vegetation. The streambeds are covered with fallen branches, tree roots, and leaf litter. The water is typically acidic, soft, and has low conductivity due to humic substances from decomposing organic material.
How it lives
These fish are pelagic and live in groups near the water surface. They feed on crustaceans and insects. Females possess larger abdomens than males. During the rainy season, they migrate upstream into tributaries and flooded forests to feed and spawn. Predators are not detailed in the provided text. Their movement is tied to seasonal water level changes, allowing access to breeding grounds in flooded areas.
Breeding and life cycle
Females lay eggs that fall to the streambed or into vegetation. At a temperature of 25 degrees Celsius, the eggs hatch after 36 hours. Spawning occurs during the rainy season when the fish move into flooded forests and tributaries. The young grow in these nutrient-rich, vegetated areas before returning to main channels.
Fish and people
The marbled hatchetfish is popular in the aquarium trade. Most individuals available commercially are caught from the wild, particularly in Brazil. Capture efforts focus on the Rio Negro region. No other uses such as food or medicine are mentioned.
Status and threats
The species is listed as Least Concern by the IUCN. While it is heavily collected for the aquarium trade, the specific effects on wild populations remain unknown.
Questions people ask about Marbled hatchetfish
What does the marbled hatchetfish eat?
Its diet consists of crustaceans and insects found near the water surface where the fish typically swim in groups.
Where does the marbled hatchetfish live?
It is found in South America, specifically in the Amazon and Orinoco drainages and coastal areas of the Guianas, preferring blackwater streams.
How big do marbled hatchetfish get?
They reach a maximum standard length of 3.5 centimetres, making them very small freshwater fish suitable for smaller aquariums.
Are marbled hatchetfish farmed or wild-caught?
Most fish in the trade are caught from the wild, primarily in Brazil, with significant collections occurring in the Rio Negro region.
Good reading and sources
- Marbled hatchetfish on WikipediaEncyclopedia
- More photos on Wikimedia CommonsPhotos
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "Marbled hatchetfish", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
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