Home / Fishes / Tetras, piranhas and pacus / Pygmy hatchetfish
No federal permit to keepPygmy hatchetfish
Carnegiella myersi
Fishes › Tetras, piranhas and pacus (Characiformes) › Gasteropelecidae (Freshwater hatchetfish)
Carnegiella myersi, the pygmy hatchetfish, is a species of freshwater ray-finned fish belonging to the family Gasteropelecidae, the freshwater hatchetfishes.
Care at a glance
Species-specific aquarium care
- Tank: At least 24 in long and 12 in front to back for one adult (adults commonly reach about 0.8 in / 2.15 cm).
- Water: Freshwater.
- Temperature: 73–79°F (range recorded for this species).
- pH: 5.5–6.5.
- Hardness: 0–20 dGH.
- Layout: An open-water swimmer: needs long, open swimming space with few obstacles.
Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.
Care guide
Species care notes
- Tank: a base of at least 20 × 12 in (roughly 12 US gallons); space needed is rated “modest tank”.
- Water: soft, acidic water, 73–79 °F, pH 4–7, 1–6 dGH.
- Behaviour: temperament peaceful; a shoaling fish best kept in a group of six or more; suited to a community tank.
- Difficulty: Easy (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “This species requires a well-matured aquarium with floating plants but providing some clear surface for swimming.”
- Diet: “Insectivore by nature, eating small insects on the water surface, it will usually accept most prepared foods that float such as flake and micro pellet, small dried insects and bloodworms.”
- Tankmates: “Very peaceful but due to its small size and rather timid nature it is not a fish for the general community tank.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Freshwater hatchetfish
Applies to most species in this group. Habitat: These South American surface fishes inhabit forest streams, tributaries and swamps with surface vegetation, with marbled hatchetfish associated particularly with blackwater and flooded forest. [fg245-sternicla, fg245-strigata]. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- Fit a very tight cover: startled hatchetfish can jump out.
- For Carnegiella strigata, provide at least 75 × 30 cm (30 × 12 inches) of surface area.
- For Gasteropelecus sternicla, the cited minimum surface area is 120 × 30 cm (48 × 12 inches).
- Provide floating plant patches and planted cover around surface swimming space.
- Use gentle to moderate current; for C. strigata, maintain soft water within the cited 1–10 dGH and pH 4.0–7.0 ranges.
Climate & lighting
| Water | 68–82.4°F |
Diet
- Gut-loaded small fruit flies offered at the surface.
- Small live or frozen Daphnia.
- Artemia nauplii for small Carnegiella.
- Frozen bloodworms and suitably sized dry foods once accepted.
Social life
- Keep at least six G. sternicla; C. strigata does best with ten or more. Choose similarly peaceful companions that do not outcompete them for food.
Health watch
- Ammonia-related illness.
- Nutritional deficiencies.
- Introduced parasitic skin or gill infections.
Understanding the animal
About this animal
About this animal
This fish is found in streams of the upper Amazon basin in Bolivia Brazil, Colombia, Ecuador and Peru. It is named for ichthyologist George S. Myers (1905–1985) of Stanford University, because of his contributions towards expanding the knowledge of South American fishes.
Quoted from the Wikipedia article “Carnegiella myersi” (CC BY-SA 4.0) 174
In the wild
In the wild
From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.1
| Where it lives | Lives in freshwater. |
| Water it lives in | Freshwater, 73–79 °F (23–26 °C), pH 5.5–6.5, hardness 20 dH. |
| Climate | Tropical climate. |
What this means for care
- Keep water within its wild range, 73–79 °F.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 89°F (up to 91°F in the hottest sampled areas) |
| Cool-season lows | about 68°F (down to 62°F in the coldest sampled areas) |
| Average temperature | 77–80°F across sampled records |
| Relative humidity | 78–85% on average (driest month about 80%) |
| Rainfall | about 2543 mm a year, spread fairly evenly |
Measured at 65 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.
From the sources
From the sources
Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.
| Overview | Carnegiella myersi, the pygmy hatchetfish, is a species of freshwater ray-finned fish belonging to the family Gasteropelecidae, the freshwater hatchetfishes. This fish is found in streams of the upper Amazon basin in Bolivia Brazil, Colombia, Ecuador and Peru. It is named for ichthyologist George S. Myers (1905–1985) of Stanford University, because of his contributions towards expanding the knowledge of South American fishes. — Wikipedia (community-edited) |
| Where it lives | Home ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase |
Data and studies
The numbers
The numbers
Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.
Adult length
Maximum recorded length. Measured as standard length (snout to the base of the tail, not counting the tail fin). Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates in nature; aim for the middle.
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 20 × 12 in (about 12 US gallons).
Sources for this sheet
- FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
- Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
- Seriously Fish: Carnegiella strigata Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Gasteropelecus sternicla Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Merck Veterinary Manual: Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
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