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Foersch's Mouthbrooder

Betta foerschi

Fishes › Gouramis, bettas, snakeheads (Anabantiformes) › Osphronemidae (Gouramis and bettas)

Betta foerschi is a species of gourami endemic to the island of Borneo, where it is only known from the southern portion.

Aquarium hobby
Experience: Beginner
FamilyGouramis and bettas
Adult lengthup to 2.8 in
WaterFreshwater

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 2.8 in / 7 cm).
  • Water: Freshwater.
  • Temperature: 75–79°F (range recorded for this species).
  • pH: 4–6.
  • Hardness: 0–4 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 24 × 12 in (roughly 14 US gallons); space needed is rated “modest tank”.
  • Water: soft, acidic water, 72–82 °F, pH 4–6, 1–5 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

Group care guide

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.

Sources 117119164118252253

Diet

  • Betta pellets plus frozen foods.

Sources 117119164118252253

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.

Sources 117119164118252253

Health watch

  • Fin rot in dirty water; never keep bettas in tiny unheated bowls.

Sources 117119164118252253

Understanding the animal

About this animal

About this animal

It inhabits creeks in the rain forest. This species grows to a length of 7 cm (2.8 in).

Quoted from the Wikipedia article “Betta foerschi” (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 livesLives in freshwater. Uses both the bottom and open water.
Water it lives inFreshwater, 75–79 °F (24–26 °C), pH 4–6, hardness 4 dH.
ClimateTropical climate.
Behavior to plan forBreeding: nesters.

What this means for care

  • Keep water within its wild range, 75–79 °F.
  1. FishBase species summary: Betta foerschi
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.

OverviewBetta foerschi is a species of gourami endemic to the island of Borneo, where it is only known from the southern portion. It inhabits creeks in the rain forest. This species grows to a length of 7 cm. It can be found in the aquarium trade. — Wikipedia (community-edited)
Where it livesHome 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
BiologyFacultative air-breathing; In rain forest creek. — 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

Average of sources2.4in
FishBase 1642.8
Seriously Fish species profiles 1672

Maximum recorded length. Measured as total length. Fish in home aquariums often stay smaller than wild records.

Water temperature

Average of sources73.5–80.5°F
FishBase 16475–79
Seriously Fish species profiles 16772–82

Range the species tolerates in nature; aim for the middle.

pH

Average of sources4–6
FishBase 1644–6
Seriously Fish species profiles 1674–6

Water hardness

Average of sources0.5–4.5dGH
FishBase 1640–4
Seriously Fish species profiles 1671–5

Minimum tank footprint

Reported24in
Seriously Fish species profiles 16724

Seriously Fish recommends a tank base of at least 24 × 12 in (about 14 US gallons).

Sources for this sheet

  1. 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.
  2. 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.
  3. Merck Veterinary Manual: Management of aquarium fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
  4. 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.
  5. Merck Veterinary Manual: Nutritional diseases of fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
  6. Seriously Fish — Betta splendens Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
  7. Seriously Fish — Betta imbellis Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
  8. Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.