Home / Fishes / Carp, barbs, minnows, loaches / Balitoridae / Hemimyzon formosanus
No federal permit to keepHemimyzon formosanus
Hemimyzon formosanus
Fishes › Carp, barbs, minnows, loaches (Cypriniformes) › Balitoridae (Hillstream loaches)
Hemimyzon formosanus is a species of hillstream loach (a ray-finned fish) in the genus Hemimyzon.
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 3.9 in / 10 cm).
- Water: Freshwater.
- Layout: Lives on or near the bottom: floor space and hiding places matter more than height.
- 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 47 × 12 in (roughly 29 US gallons); space needed is rated “large tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 61–72 °F, pH 6.5–8, 2–15 dGH.
- Behaviour: temperament peaceful; a shoaling fish best kept in a group of six or more; not a community fish.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Most importantly the water must be clean and well-oxygenated so we suggest the use of an over-sized filter as a minimum requirement.”
- Diet: “Much of the natural diet is likely to be composed of benthic algae plus associated micro-organisms which are rasped from solid surfaces.”
- Tankmates: “Largely peaceful although its environmental requirements limit the choice of suitable tankmates somewhat, so research your choices before purchase in order to be sure.”
- Breeding: “Presumably a seasonal spawner in nature but nothing has been recorded in aquaria.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Hillstream loaches
Applies to most species in this group. Habitat: Balitora inhabit fast-flowing Asian hillstream riffles with rocky beds and abundant dissolved oxygen. [fg177-bal]. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- Use a long river aquarium; the river-tank reference recommends at least 3 feet of length, rather than a species-tested minimum.
- Provide strong directional current and vigorous aeration throughout the occupied area.
- Supply smooth pebbles, boulders and numerous rocky refuges out of the main current.
- Use bright lighting and an established aquarium with grazing growth on rocks.
- For B. brucei, maintain pH 7.0–8.0 and medium hardness up to 12 dGH.
Climate & lighting
| Water | 68–75°F |
Diet
- Algae and established rock biofilm.
- Frozen bloodworms and mysis shrimp.
- Pelleted foods.
Social life
- Provide separate resting and feeding surfaces; hillstream keepers report competition for favored rocks, but a Balitora-specific group size is not established here.
Health watch
- Oxygen deprivation, especially during overheating or inadequate aeration.
- Poor condition from inadequate access to established grazing growth.
- Skin disease with patchy coloration and loss of appetite; obtain a diagnosis rather than treating by appearance alone.
Understanding the animal
About this animal
About this animal
It is endemic to western portion of Central Mountain Range of Taiwan. Its maximum length is 10 cm (3.9 in).
Quoted from the Wikipedia article “Hemimyzon formosanus” (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. Stays near the bottom. |
| Water it lives in | Freshwater, depth 0–10 m. |
| Climate | Subtropical climate. |
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 83°F (up to 88°F in the hottest sampled areas) |
| Cool-season lows | about 49°F (down to 36°F in the coldest sampled areas) |
| Average temperature | 52–73°F across sampled records |
| Relative humidity | 81–85% on average (driest month about 78%) |
| Rainfall | about 2405 mm a year |
Measured at 15 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 | Hemimyzon formosanus is a species of hillstream loach (a ray-finned fish) in the genus Hemimyzon. It is endemic to western portion of Central Mountain Range of Taiwan. Its maximum length is 10 cm. Variations in nucleotide sequences within the mitochondrial control region show strong geographic structuring suggestive of a cryptic species complex. — 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 |
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 47 × 12 in (about 29 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.
- Loaches Online: Balitora brucei Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Loaches Online: Hillstream Loaches — The Specialists at Life In The Fast Lane Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Merck Veterinary Manual: Disorders and Diseases of Fish 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.
More hillstream loaches
Green Gecko Loach
Homalopteroides smithi
Aquarium hobby
Green Lizard Hillstream
Homalopteroides tweediei
Aquarium hobby
Homaloptera bilineata
Homaloptera bilineata
Aquarium hobby
Homaloptera confuzona
Homaloptera confuzona
Aquarium hobby
Homaloptera ogilviei
Homaloptera ogilviei
Aquarium hobby
Homaloptera orthogoniata
Homaloptera orthogoniata
Aquarium hobby