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No federal permit to keepGreen Gecko Loach
Homalopteroides smithi
Fishes › Carp, barbs, minnows, loaches (Cypriniformes) › Balitoridae (Hillstream loaches)
Homalopteroides smithi is a species of ray-finned fish in the genus Homalopteroides.
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 / 9.8 cm).
- Water: Freshwater.
- Layout: Lives on or near the bottom: floor space and hiding places matter more than height.
- Diet: FishBase classes it as a carnivore.
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: a fairly wide range, from slightly acidic to slightly alkaline, 68–78 °F, pH 6–7.5, 1–12 dGH.
- Behaviour: 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.”
- Tankmates: “Not an aggressive fish although its particular requirements limit the choice of suitable tankmates.”
- 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 can be found in the Mekong and Chao Phraya basins and Malay Peninsula. The fish is named in honor of ichthyologist Hugh McCormick Smith (1865–1941), then at the Siam Department of Fisheries, in what is now Thailand.
Quoted from the Wikipedia article “Homalopteroides smithi” (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, in rivers and streams. Stays near the bottom. Adults inhabit high gradient streams over fast bedrock, cobble runs and rapids while juveniles in slower stretches of gravel and exposed tree roots. |
| Water it lives in | Freshwater. |
| Climate | Tropical climate. |
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 92°F (up to 95°F in the hottest sampled areas) |
| Cool-season lows | about 65°F (down to 55°F in the coldest sampled areas) |
| Average temperature | 75–81°F across sampled records |
| Relative humidity | 72–78% on average (driest month about 64%) |
| Rainfall | about 1826 mm a year, with strong wet and dry seasons |
Measured at 73 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 | Homalopteroides smithi is a species of ray-finned fish in the genus Homalopteroides. It can be found in the Mekong and Chao Phraya basins and Malay Peninsula. The fish is named in honor of ichthyologist Hugh McCormick Smith (1865–1941), then at the Siam Department of Fisheries, in what is now Thailand. Other common names include the Green Gecko Loach or Shi's Flatfin Loach (a direct translation of the fish's chinese name '史氏平鰭鰍'). — 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 | Adults inhabit high gradient streams over fast bedrock, cobble runs and rapids while juveniles in slower stretches of gravel and exposed tree roots. Found in rapid-running mountain streams of the middle Mekong. Feed on aquatic insect larvae, particularly Odonatans. — 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.
Typical adult weight
Average adult body mass in each database (FishBase gives the maximum recorded weight).
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 24 × 12 in (about 14 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.
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