Home / Fishes / Gouramis, bettas, snakeheads / Penang betta
No federal permit to keepPenang betta
Betta pugnax
Fishes › Gouramis, bettas, snakeheads (Anabantiformes) › Osphronemidae (Gouramis and bettas)
The Penang betta (Betta pugnax)—also known as Sepilai, the Malayan forest betta, or Malayan betta—is a species of gourami native to Southeast Asia and common in swiftly flowing forest streams of the Malay Peninsula, Thailand, Sumatra, and the Riau Islands.
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 / 6.73 cm).
- Water: Freshwater.
- Temperature: 75–82°F (range recorded for this species).
- pH: 7.1–7.6.
- Hardness: 5–12 dGH.
- Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.
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 31 × 12 in (roughly 19 US gallons); space needed is rated “modest tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 72–82 °F, pH 4–7.5, 1–10 dGH.
- Behaviour: temperament species tank; in a pair; not a community fish.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Can be maintained in a fully-decorated aquarium although many breeders prefer not to use a substrate for ease of maintenance.”
- Diet: “Likely to prey on aquatic and terrestrial invertebrates in nature.”
- Tankmates: “Not recommended for the standard community aquarium.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Bettas (fighting fish)
Applies to most species in this group. Habitat: Shallow rice paddies and marshes. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- A heated, filtered tank of at least 5 gallons, with gentle flow and plants.
- Domestic B. splendens should generally be maintained alone. Other Betta species need their own compatibility plan; B. imbellis can be maintained as a pair with adequate cover.
Diet
- Betta pellets plus frozen foods.
Social life
- Use species-specific social housing: B. splendens alone under the detailed Seriously Fish recommendation; B. imbellis may be housed as a compatible pair.
Health watch
- Fin rot in dirty water; never keep bettas in tiny unheated bowls.
Understanding the animal
About this animal
About this animal
It can be found amongst the vegetation growing along the banks. This species can reach a length of 6.7 centimetres (2.6 in) SL. It is one of the mouthbrooding Betta species.
Quoted from the Wikipedia article “Penang betta” (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. Uses both the bottom and open water. Occurs in small fast flowing forest streams. |
| Water it lives in | Freshwater, 75–82 °F (24–28 °C), pH 7.1–7.6, hardness 5–12 dH. |
| Climate | Tropical climate. |
| Behavior to plan for | Breeding: external brooders. |
What this means for care
- Keep water within its wild range, 75–82 °F.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 89°F (up to 92°F in the hottest sampled areas) |
| Cool-season lows | about 72°F (down to 67°F in the coldest sampled areas) |
| Average temperature | 76–81°F across sampled records |
| Relative humidity | 80–85% on average (driest month about 79%) |
| Rainfall | about 2376 mm a year, spread fairly evenly |
Measured at 42 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 Penang betta (Betta pugnax)—also known as Sepilai, the Malayan forest betta, or Malayan betta—is a species of gourami native to Southeast Asia and common in swiftly flowing forest streams of the Malay Peninsula, Thailand, Sumatra, and the Riau Islands. It can be found amongst the vegetation growing along the banks. This species can reach a length of 6.7 centimetres (2.6 in) SL. It is one of the mouthbrooding Betta species. — 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 | Wild Penang betas are mainly insectivores, feeding on insects and their larvae. However, they have also been recorded eating invertebrates. Researchers have conducted experiments on B. pugnax's ability to hunt and consume mosquito larvae. — Wikipedia (community-edited) |
| Reproduction | Spawns in a depression on the substrate. Male broods the eggs in his mouth until hatching. Produces a minimum of 100 eggs. — FishBase |
| Appearance and size | The Penang betta is described as having a superior mouth —a common trait among the betta genus—and a larger than average head. Other differences from members of the betta family include a stouter body, present chin-bar, visible dorsal transverse bars, red subdistal bands and black edges around their anal-fins, and no dark edge on caudal fins. — Wikipedia (community-edited) |
| Biology | Facultative air-breathing; Occurs in small fast flowing forest streams. Inhabits mainly overhanging bank vegetation, submerged leaf litter and exposed roots of bank vegetation (, 56613 ). — FishBase |
| History and naming | There is evidence B. pugnax was imported into Germany as early back as 1905, though they never reached the level of popularity B. splendens—better known as the Siamese Fighting Fish—achieved. Betta fighting—a native sport of Thailand—created a unique environment in which selective breeding could be observed. — 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 in nature; aim for the middle.
Minimum tank footprint
Seriously Fish recommends a tank base of at least 31 × 12 in (about 19 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.
- Seriously Fish — Betta splendens Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Seriously Fish — Betta imbellis 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.
- 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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