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No federal permit to keepSpotfin hatchetfish
Thoracocharax stellatus
Fishes › Tetras, piranhas and pacus (Characiformes) › Gasteropelecidae (Freshwater hatchetfish)
Thoracocharax stellatus, the silver hatchetfish, spotfin hatchetfish, spotted hatchetfish or platinum hatchetfish, is a species of freshwater ray-finned fish belonging to the family Gasteropelecidae, the freshwater hatchet fishes.
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 2.6 in / 6.7 cm).
- Water: Freshwater.
- 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 47 × 18 in (roughly 64 US gallons); space needed is rated “large tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 68–82 °F, pH 5–7.5, 1–12 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: “Cover a good portion of the water surface with floating plants, which will help to make this flighty species less skittish.”
- Diet: “Remaining close to the shore, it feeds primarily on insects; a study (Netto-Ferreira et al, 2007) [2] determined that 99.6% of the diet of this fish consists of insects, and the majority (87.6%) of these were terrestrial.”
- Tankmates: “Very peaceful but it can be nervous, and will not compete well with boisterous species for food.”
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 species is found throughout tropical and subtropical South America in the Amazon, Orinoco, Paraguay and Tocantins-Araguaia basins. This species is one of the largest of the hatchetfishes.
Quoted from the Wikipedia article “Thoracocharax stellatus” (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. Aquarium specimens reach cm TL. |
| Water it lives in | Freshwater. |
| Climate | Tropical climate. |
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 91°F (up to 95°F in the hottest sampled areas) |
| Cool-season lows | about 69°F (down to 58°F in the coldest sampled areas) |
| Average temperature | 76–81°F across sampled records |
| Relative humidity | 73–82% on average (driest month about 66%) |
| Rainfall | about 1854 mm a year |
Measured at 406 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 | Thoracocharax stellatus, the silver hatchetfish, spotfin hatchetfish, spotted hatchetfish or platinum hatchetfish, is a species of freshwater ray-finned fish belonging to the family Gasteropelecidae, the freshwater hatchet fishes. This species is found throughout tropical and subtropical South America in the Amazon, Orinoco, Paraguay and Tocantins-Araguaia basins. This species is one of the largest of the hatchetfishes. It is usually found in areas with abundant riparian vegetation. — 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 |
| Wild diet | In the wild, feeding occurs at sunrise and sunset, and analysis of the stomach contents of 88 specimens indicates that this species is mostly insectivorous (99.6% of stomach contents were insects). Its food consists mostly of ants, beetles, and mayflies. Thoracocharax stellatus appears to be a specialist on terrestrial insects, and feeds by leaping out of the water and taking insects from riparian vegetation. — Wikipedia (community-edited) |
| Appearance and size | Thoracocharax stellatus is superficially similar to Thoracocharax securis, but has a prominent dark spot on the dorsal fin. In the wild, adults vary in length between 21 and 55mm, but in captivity can grow up to between 60 and 70mm. Its maximum length is 80mm. — Wikipedia (community-edited) |
| Biology | Aquarium specimens reach cm TL. — FishBase |
| History and naming | Thoracocharax stellatus was first formally described as Gastropelecus stellatus in 1858 by the Austrian ichthyologist Rudolf Kner, with its type locality given as the Rio Cuiabá in Brazil. In 1907, Henry Weed Fowler proposed a new subgenus, Thoracocharax, of the genus Gasteropelecus, and designated G. stellaris as its type species. It was also the only species then classified in the subgenus. — Wikipedia (community-edited) |
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; aim for the middle.
pH
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 47 × 18 in (about 64 US gallons).
Veterinary & husbandry research
Veterinary & husbandry research
- Against the mainstream: exceptional evolutionary stability of ZW sex chromosomes across the fish families Triportheidae and Gasteropelecidae (Teleostei: Characiformes) Yano CF et al., Chromosome research: an international journal on the molecular, supramolecular and evolutionary aspects of chromosome biology 2021
Peer-reviewed papers that mention this species alongside captivity, zoos, veterinary care or aquaculture. Some cover several species or mention it only in passing, so check the abstract. 170
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.
- PubMed (U.S. National Library of Medicine) Peer-reviewed researchIndex of peer-reviewed veterinary, zoo and husbandry research.
- iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.
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Common hatchetfish
Gasteropelecus sternicla
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Marbled hatchetfish
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Pygmy hatchetfish
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Silver hatchetfish
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