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Home / Fishes / Carp, barbs, minnows, loaches / Nemacheilidae / Rheostura pridii

No federal permit to keep

Rheostura pridii

Schistura pridii

Also known as Dr. Pridi’s Loach

Fishes › Carp, barbs, minnows, loaches (Cypriniformes) › Nemacheilidae (Stone loaches)

Schistura pridii is a species of freshwater ray-finned fish belonging to the family Nemacheilidae, the stone loaches.

Aquarium hobby
Experience: Intermediate
FamilyStone loaches
Adult lengthup to 1.6 in
WaterFreshwater
HabitatLives in freshwater

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 1.5 in / 3.8 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 24 × 12 in (roughly 14 US gallons); space needed is rated “modest tank”.
  • Water: a fairly wide range, from slightly acidic to slightly alkaline, 64–75 °F, pH 7–8.5, 5–15 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: “Not difficult to maintain under the correct conditions; we strongly recommend keeping it in a tank designed to resemble a flowing stream or river with a substrate of variably-sized rocks, sand, fine gravel, and some water-worn boulders.”
  • Diet: “Naturally a micropredator feeding on small insects, worms, crustaceans, and other zooplankton with only relatively small amounts of plant matter and other organic detritus consumed.”
  • Tankmates: “Best maintained alone or alongside comparably-sized, peaceful fishes which inhabit similar biotopes in nature, especially those which swim in open water such as Microdevario, species.”

From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167

Group care guide

Stone loaches

Applies to most species in this group. Habitat: Eurasian stone loaches include oxygen-rich stream dwellers such as Schistura and small Vietnamese river species such as the hovering zebra loach. [fg157-sumo, fg157-hover]. Individual species can differ, so compare with the species numbers above and the linked sources.

Level 3 reflects water-quality and compatibility demands. Water range is for S. balteata; hovering zebra loaches accept 71.6–80.6°F and are called Micronemacheilus cruciatus in the source. [fg157-sumo, fg157-hover] Do not apply the tropical Schistura setup automatically to Hedinichthys, Barbatula, Lefua, Homatula or S. fasciolata: the cited protocols do not establish their temperature or flow needs.

Housing & setup

  • For Schistura balteata groups use a floor at least 90 × 30 cm (36 × 12 in).
  • Build a stream layout with sand, rounded rocks and driftwood forming numerous caves and broken sight lines.
  • Use strong filtration, aeration and some flow for Schistura; change 30–50% of water weekly.
  • For hovering zebra loaches use at least 60 × 30 cm (24 × 12 in), dense plants and well-oxygenated but non-turbulent water.
  • Introduce hovering zebra loaches only to a biologically mature aquarium; pH 6.0–7.5 and hardness 2–12 dGH suit both profiled species.

Sources 870871872

Climate & lighting

Water71.6–78.8°F

Sources 870871872

Diet

  • Small live or frozen Daphnia and Artemia.
  • Bloodworms for Schistura.
  • Moina, microworms and Artemia nauplii for hovering zebra loaches.
  • Appropriately sized dried foods alongside invertebrates, not as the sole Schistura diet.

Sources 870871872

Social life

  • Schistura defend individual caves and can harass placid bottom dwellers; groups require territories. Hovering zebra loaches are peaceful and need at least 8–10 companions.

Sources 870871872

Health watch

  • Territorial fin injuries in poorly structured Schistura tanks.
  • Freshwater ich, a general aquarium risk.
  • Stress-associated bacterial infections.

Sources 870871872

Understanding the animal

This species is part of a group that hobbyists, aviculturists or zoos keep widely (Stone loaches), so it's included for completeness. It may be rare in captivity itself, or not kept at all. Use the group guide as a starting point and look for species-specific advice from experienced keepers.
About this animal

About this animal

It is found in the upper Chao Phraya basin, in streams in the Doi Chiang Dao Wildlife Sanctuary, Chiang Mai Province in Thailand. Here it inhabits torrents, with rocky gravel and pebble substrates in which it often hides.

Quoted from the Wikipedia article “Rheostura pridii” (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, in rivers and streams. Stays near the bottom. Found in shallow, torrential hill streams, 0.3-1.0 m deep with gravel bottom and rocky crevices, in mixed deciduous forests, at 950-1120 m altitude.
Water it lives inFreshwater, depth 0–1 m.
ClimateTropical climate.
  1. FishBase species summary: Schistura pridii
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.

OverviewSchistura pridii is a species of freshwater ray-finned fish belonging to the family Nemacheilidae, the stone loaches. It is found in the upper Chao Phraya basin, in streams in the Doi Chiang Dao Wildlife Sanctuary, Chiang Mai Province in Thailand. Here it inhabits torrents, with rocky gravel and pebble substrates in which it often hides. This species reaches a standard length of 3.8 cm. — 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
BiologyFound in shallow, torrential hill streams, 0.3-1.0 m deep with gravel bottom and rocky crevices, in mixed deciduous forests, at 950-1120 m altitude. — 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 sources1.6in
FishBase 1641.5
Seriously Fish species profiles 1671.6

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

Reported64–75°F
Seriously Fish species profiles 16764–75

Range the species tolerates; aim for the middle.

pH

Reported7–8.5
Seriously Fish species profiles 1677–8.5

Water hardness

Reported5–15dGH
Seriously Fish species profiles 1675–15

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. Seriously Fish: Schistura balteata Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
  4. Seriously Fish: Micronemacheilus cruciatus (formerly Yunnanilus cruciatus) Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
  5. Merck Veterinary Manual: Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
  6. Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.