Care guide · Freshwater · fish
Spotfin hatchetfish
Thoracocharax stellatus
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The spotfin hatchetfish, Thoracocharax stellatus, is a large South American surface fish in the family Gasteropelecidae. It is sometimes sold as the platinum hatchetfish. Confusion with its close relative T. securis and with larger Gasteropelecus species is possible. Seriously Fish identifies a prominent dark spot in the dorsal fin as a distinguishing feature from T. securis. Check the complete fish; a trade name or shiny colour alone is not enough. This guide covers T. stellatus only. Its adult size and substantial tank footprint should be planned before acquiring a shoal, rather than judged by volume alone.
Plan your aquarium →At a glance
- Temperature
- 20–28 °C
- pH
- 5.0–7.5
- GH
- 1–12 °dGH
- Aquarium length
- At least 120 cm
- Minimum aquarium volume
- At least 243 L
- Adult size
- At least 7 cm
- Group size
- At least 6 individuals
- Temperament
- Peaceful
About this species
Seriously Fish reports about 70 mm standard length. Standard length is measured to the base of the tail, whereas total length includes the caudal fin. Do not confuse these measurements when selecting tankmates or estimating space. The deep, laterally compressed chest and large pectoral fins are characteristic of hatchetfishes. Despite descriptions of a ‘flying fish’, it makes powerful leaps out of water; its pectoral fins do not produce sustained flight.Natural habitat
The species has been recorded across much of South America, including the Amazon, Orinoco and Paraná drainages. Records come from blackwater and clearwater streams, tributaries, backwaters and inundated floodplains. Surface vegetation is often abundant. Floating plants offer cover, while a mix of some current and quieter areas provides environmental choice. Its broad range does not establish one exact local water profile or a single fixed biotope.Aquarium and layout
Seriously Fish recommends a minimum base and surface area of 120 by 45 cm, about 243 litres, and says this should be the smallest size considered. Length and width matter alongside volume. Keep at least six fish for shoal security. A strong, tightly fitting lid is essential because startled hatchetfish can jump several metres. Provide floating cover, open swimming room, some current and sheltered calm areas.Water conditions
Seriously Fish lists 20–28°C, pH 5.0–7.5 and GH 1–12 dGH. These are broad boundaries, not target values that must be actively pursued. Keep water quality stable and acclimate fish with regard to their previous conditions. Use suitable test equipment. Abrupt changes can cause stress even when the new reading falls inside a published range.Behaviour and group size
The spotfin hatchetfish is peaceful but can be nervous and may lose food to boisterous tankmates. Choose calm fish that mainly use other parts of the aquarium and cannot be swallowed as prey. Also assess shoaling behaviour, food competition, adult size and the substantial tank footprint. A matching temperature alone does not prove a suitable combination. Avoid adding small, timid species if they would be consistently outcompeted.Feeding
A field study summarized by Seriously Fish found that 99.6 percent of the diet consisted of insects, most of them terrestrial. Offer small insects, fruit flies, mosquito larvae, Daphnia and suitable dry foods, live, frozen or dried. Some fish initially refuse dry food. Unlike small Carnegiella, T. stellatus can also descend to take sinking items. Still observe the group to ensure every fish receives enough food.Breeding
Seriously Fish lists reproduction as unrecorded. The reviewed material does not provide a reliable routine for breeding this species in a home aquarium. There is therefore no basis to promise a particular spawning method, parental care or success. Focus on a spacious, stable shoal, appropriate food and a secure cover. Do not transfer breeding methods from related hatchetfishes without evidence.Sources & review
This care guide draws on several specialist sources and was last checked on .