Home / Fishes / Carp, barbs, minnows, loaches / Danionidae / Three-spotted dwarf minnow
No federal permit to keepThree-spotted dwarf minnow
Boraras micros
Fishes › Carp, barbs, minnows, loaches (Cypriniformes) › Danionidae (Danios and rasboras)
The three-spotted dwarf minnow (Boraras micros) is a species of ray-finned fish in the genus Boraras. The Dwarf Minnow is typically characterized by three striking black dots (one on the base of its anal fin, one on the side, and one on its caudal fin).
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 0.5 in / 1.33 cm).
- Water: Freshwater.
- Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.
- Availability: Rarely or never seen in the aquarium trade; expect to source it from specialists or not at all.
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 18 × 12 in (roughly 11 US gallons); space needed is rated “modest tank”.
- Water: soft, acidic water, 68–82 °F, pH 6–7, 2–10 dGH.
- Behaviour: temperament peaceful; a shoaling fish best kept in a group of six or more; suited to a community tank.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Best kept in a densely-planted aquarium and is an excellent choice for the carefully-aquascaped set-up.”
- Diet: “As with other Boraras species it is likely to be a micropredator feeding on small insects, worms, crustaceans and other zooplankton in nature.”
- Tankmates: “This species is very peaceful but does not make an ideal community fish due to its small size and rather timid nature.”
- Breeding: “May not have been bred in captivity although it should certainly be possible.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Danios and rasboras
Applies to most species in this group. Habitat: These Asian fishes occupy habitats ranging from zebra-danio pools and rice paddies to shaded harlequin streams, rocky Devario streams and planted galaxy-rasbora wetlands. [fg159-zebra, fg159-harlequin, fg159-giant, fg159-galaxy]. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- Use at least 90 × 30 cm (36 × 12 in) for zebra danios.
- Harlequins require at least 60 × 30 cm (24 × 12 in), shaded planted cover and subdued light.
- Devario aequipinnatus needs at least 120 × 45 cm (48 × 18 in), oxygenated water, moderate flow and a tight lid.
- Galaxy rasboras need dense planting and broken sight lines in at least 45 × 30 cm (18 × 12 in), with gentle sponge filtration.
- Match chemistry: harlequins pH 5.0–7.5, 1–12 dGH; galaxy rasboras pH 6.5–7.5, 5–15 dGH.
Climate & lighting
| Water | 64.4–77°F |
Diet
- Quality flakes or granules sized to the fish.
- Live or frozen Daphnia and Artemia.
- Bloodworms for zebra danios, harlequins and Devario.
- Small sinking foods for galaxy rasboras, which rarely feed at the surface.
Social life
- Keep zebra danios and harlequins in groups of at least 8–10. Galaxy males spar: dense cover and larger groups distribute aggression. Active Devario can overwhelm timid feeders.
Health watch
- Pseudoloma microsporidiosis in zebra danios.
- Pleistophora infection and columnaris can produce similar white lesions in zebra danios.
- Nipped fins among rival galaxy males.
Understanding the animal
About this animal
About this animal
One way to distinguish the female minnows from the males is the phenotype alone.
Quoted from the Wikipedia article “Three-spotted dwarf minnow” (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. Inhabits swamps and ponds with clear, relatively deep water. |
| Water it lives in | Freshwater. |
| Climate | Tropical climate. |
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 three-spotted dwarf minnow (Boraras micros) is a species of ray-finned fish in the genus Boraras. The Dwarf Minnow is typically characterized by three striking black dots (one on the base of its anal fin, one on the side, and one on its caudal fin). One way to distinguish the female minnows from the males is the phenotype alone. Females appear larger and have more pronounced, rounded abdomens. — 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 |
| Biology | Inhabits swamps and ponds with clear, relatively deep water. — 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 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 18 × 12 in (about 11 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.
- Seriously Fish: Zebra danio (Danio / Brachydanio rerio) Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Trigonostigma heteromorpha Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Devario aequipinnatus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Danio / Celestichthys margaritatus Experienced keeper or breederAdded 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.
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