Home / Fishes / Ricefish, halfbeaks, needlefish / Wrestling halfbeak
No federal permit to keepWrestling halfbeak
Dermogenys pusilla
Fishes › Ricefish, halfbeaks, needlefish (Beloniformes) › Zenarchopteridae (Livebearing halfbeaks)
The wrestling halfbeak (Dermogenys pusilla) also known as Malayan halfbeak is a species of viviparous halfbeak native to the fresh and brackish waters of rivers and coastal regions in South-East Asia, in Singapore, Indonesia, Thailand, Malaysia,…
Care at a glance
Species-specific aquarium care
- Tank: At least 36 in long and 12 in front to back for one adult (adults commonly reach about 6.3 in / 16.1 cm).
- Water: Freshwater (tolerates brackish).
- Temperature: 75–82°F (range recorded for this species).
- pH: 7–8.
- Hardness: 9–19 dGH.
- Layout: An open-water coastal swimmer: needs long, open swimming space.
- Diet: A predator: feed meaty foods sized to its mouth (frozen fish, shrimp, worms); it will eat tankmates that fit in its mouth. FishBase classes it as a carnivore.
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 24 × 15 in (roughly 18 US gallons); space needed is rated “modest tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 75–82 °F, pH 6.5–8, 10–20 dGH.
- Difficulty: Easy (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Surface area is more important than depth with this species, as it spends almost all of its time just under the water surface.”
- Diet: “Feeds exclusively from the surface.”
- Tankmates: “Can be kept with similarly-sized, peaceful species that enjoy the same water conditions.”
- Breeding: “Not as easy to breed as many livebearers, although it is certainly possible.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Fishes
Applies to most species in this group. Habitat: Varies. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- Cycle the aquarium before adding fish so beneficial bacteria can handle ammonia and nitrite.
- Size filtration and partial water changes to stocking and measured water quality. Topping up evaporated water does not replace a water change; treat incoming tap water appropriately.
- Test ammonia, nitrite, nitrate and pH regularly.
Diet
- A varied diet of quality prepared foods plus frozen or live foods suited to the species; feed only what's eaten in a few minutes.
Health watch
- Quarantine new fish for at least 30 days; longer may be needed. Use a separate system and dedicated nets, buckets and siphons.
- Never release aquarium fish or plants into the wild.
Understanding the animal
About this animal
About this animal
It is a small, slender, livebearing fish, with the elongated lower jaw characteristic of its family. The colour of this species varies, depending on where the specimen is found.
Quoted from the Wikipedia article “Wrestling halfbeak” (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 and brackish water and the sea, in rivers and streams, estuaries, mangroves. Swims in open water near the coast. Found in rivers, rivulets, canals, drains, ponds and lakes. |
| Water it lives in | Freshwater / brackish water / marine, 75–82 °F (24–28 °C), pH 7–8, hardness 9–19 dH. |
| Climate | Tropical climate. |
| Wild diet | Hunting macrofauna (predator). |
| Behavior to plan for | Breeding: internal live bearers. |
What this means for care
- Keep water within its wild range, 75–82 °F.
- It tolerates or needs brackish water; check salinity needs before setup.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 89°F (up to 94°F in the hottest sampled areas) |
| Cool-season lows | about 70°F (down to 61°F in the coldest sampled areas) |
| Average temperature | 75–81°F across sampled records |
| Relative humidity | 76–82% on average (driest month about 72%) |
| Rainfall | about 2185 mm a year |
Measured at 57 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 | The wrestling halfbeak (Dermogenys pusilla) also known as Malayan halfbeak is a species of viviparous halfbeak native to the fresh and brackish waters of rivers and coastal regions in South-East Asia, in Singapore, Indonesia, Thailand, Malaysia, Borneo and Sumatra. It is a small, slender, livebearing fish, with the elongated lower jaw characteristic of its family. The colour of this species varies, depending on where the specimen is found. It is the type species of the genus Dermogenys. — 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 |
| Reproduction | Gives birth to 10-30 young. — FishBase |
| Biology | Found in rivers, rivulets, canals, drains, ponds and lakes. Rarely found in the sea. Inhabits medium to large rivers, flooded fields and mainly stagnant waters including sluggish flowing canals of the lower Mekong. — 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 total length. 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 24 × 15 in (about 18 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.
- Merck Veterinary Manual: Management of aquarium fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
- Merck Veterinary Manual: Types and features of aquatic systems Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
- Merck Veterinary Manual: Nutritional diseases of fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
- 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.