Home / Fishes / Carp, barbs, minnows, loaches / Gastromyzontidae / Formosania lacustris
No federal permit to keepFormosania lacustris
Formosania lacustris
Fishes › Carp, barbs, minnows, loaches (Cypriniformes) › Gastromyzontidae (Hillstream loaches)
Care follows the hillstream loaches guide below.
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 4.7 in / 12 cm).
- Water: Freshwater.
- Layout: Lives on or near the bottom: floor space and hiding places matter more than height.
- Diet: A grazer on plants and algae: base the diet on vegetable foods (algae wafers, blanched vegetables, spirulina). FishBase classes it as a herbivore.
- 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, 68–75 °F, pH 6–7.5, 1–12 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: “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: “Little is known of this species' natural diet although presumably it feeds on crustaceans, insect larvae and other invertebrates since it shows a preference for small, meaty items such as bloodworm, Artemia, Mysis, etc.”
- 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 as far as we know.”
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
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, in rivers and streams. Stays near the bottom. Inhabits rapid flowing streams. Feeds on periphytic algae on rock surfaces. |
| Water it lives in | Freshwater, depth 1–10 m. |
| Climate | Subtropical climate. |
| Wild diet | Grazing on aquatic plants. |
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 84°F (up to 88°F in the hottest sampled areas) |
| Cool-season lows | about 52°F (down to 43°F in the coldest sampled areas) |
| Average temperature | 59–71°F across sampled records |
| Relative humidity | 80–84% on average (driest month about 78%) |
| Rainfall | about 2490 mm a year |
Measured at 10 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.
| 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 rapid flowing streams. Feeds on periphytic algae on rock surfaces. — 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; 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.
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