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Jonklaas' s loach

Lepidocephalichthys jonklaasi

Fishes › Carp, barbs, minnows, loaches (Cypriniformes) › Cobitidae (Spined loaches)

Lepidocephalichthys jonklaasi, known as the Jonklaas's loach or the spotted loach, is an endemic fish species restricted to the wet zone of Sri Lanka.

Aquarium hobby
Experience: Easy
FamilySpined loaches
Adult lengthup to 2.4 in
WaterFreshwater

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 2.4 in / 6 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, 68–77 °F, pH 5.5–7.5, 2–15 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: “Should not prove difficult to keep but must be provided with a soft, sandy substrate since some of its time will be spent completely buried, or with only eyes protruding.”
  • Diet: “Probably a micropredator sifting mouthfuls of substrate through the gills from which insect larvae, small crustaceans and suchlike are extracted.”

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

Group care guide

Spined loaches

Applies to most species in this group. Habitat: Spined loaches inhabit freshwater bottoms from tropical Pangio forest streams and swamps to temperate weather-loach streams, wetlands and paddy fields. Individual species can differ, so compare with the species numbers above and the linked sources.

The water range is for tropical P. semicincta; weather loaches require about 64–74°F for general care and should not be maintained as tropical fish indefinitely. Do not transfer these settings automatically to Cobitis paludica, taenia or sinensis, or Acantopsis dialuzona: verify species-specific care. Fish sold as P. kuhlii are often P. semicincta or relatives. Weather loaches are invasive outside their native range; the cited profile recommends indoor containment rather than outdoor maintenance. Level 2 describes the common Pangio/weather-loach pathway, not every cobitid.

Housing & setup

  • For Pangio semicincta, provide at least a 60 × 30 cm (24 × 12 in) footprint; adult Misgurnus anguillicaudatus need at least 120 × 45 cm (48 × 18 in).
  • Use soft sand for burrowing; coarse gravel can injure fish and inhibit feeding.
  • Provide shaded retreats beneath secured wood or smooth rocks, with leaf litter and low-light plants for Pangio.
  • Cover the aquarium securely and protect filter intakes against entry by small loaches.
  • Use mature biological filtration, gentle circulation and surface agitation rather than strong flow for Pangio and weather loaches.

Sources 892893894

Climate & lighting

Water70–79°F

Sources 892893894

Diet

  • Sinking complete foods reaching the bottom.
  • Live or frozen Daphnia and Artemia.
  • Bloodworms and small worms as part of a varied diet.

Sources 892893894

Social life

  • Keep Pangio in groups of at least five or six with peaceful companions. Weather loaches can be kept singly but appear more active with conspecifics; they may eat eggs, fry or tiny fish.

Sources 892893894

Health watch

  • Skin injuries and feeding impairment from unsuitable burrowing substrate.
  • Ammonia-related illness in immature aquaria.
  • Nutritional deficiencies if bottom dwellers receive insufficient suitable food.

Sources 892893894

Understanding the animal

This species is part of a group that hobbyists, aviculturists or zoos keep widely (Spined 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

The species was first recorded from the Wilpita area (Daraniyagala 1952). It is currently known from 12 locations in the wet zone including Beraliya, Dombagaskandha, Madakada, Gilimale, Hiyare, Kottawa, Kanneliya, Weddagala, Nakiyadeniya, Pahiyangala and Boralugoda.

Quoted from the Wikipedia article “Lepidocephalichthys jonklaasi” (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. Stays near the bottom. Not enough is known of the biology of this species. Inhabits shallow, slow-flowing rivulets, heavily shaded, with leaf debris.
Water it lives inFreshwater.
ClimateTropical climate.
Behavior to plan forBreeding: open water/substratum egg scatterers.
  1. FishBase species summary: Lepidocephalichthys jonklaasi
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.

OverviewLepidocephalichthys jonklaasi, known as the Jonklaas's loach or the spotted loach, is an endemic fish species restricted to the wet zone of Sri Lanka. The species was first recorded from the Wilpita area (Daraniyagala 1952). It is currently known from 12 locations in the wet zone including Beraliya, Dombagaskandha, Madakada, Gilimale, Hiyare, Kottawa, Kanneliya, Weddagala, Nakiyadeniya, Pahiyangala and Boralugoda. It is recorded from a wide range of altitudes. — 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
ReproductionBreeding of this has not observed either in the wild or captive conditions. — Wikipedia (community-edited)
Appearance and sizeMembers of the genus Lepidocephalichthys have a sharp, erectile spine on their cheeks. In some species the spine is sharp enough to puncture easily one's hand during handling of the live fish. However, it is not venomous or harmful. — Wikipedia (community-edited)
BiologyFacultative air-breathing in the genus; Not enough is known of the biology of this species. Inhabits shallow, slow-flowing rivulets, heavily shaded, with leaf debris. This fish is not visible from the water surface, being concealed beneath leaf debris. — FishBase
ConservationAccording to the 2007 red list of threatened fauna and flora of Sri Lanka, Lepidocephalichthys jonklaasi (Deraniyagala, 1956) is listed in the Endangered category. In the previous redlist published in 2002 it was listed as Endangered as well. In the 1999 red list it has been listed as Threatened species. — Wikipedia (community-edited)

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 sources2.1in
FishBase 1642.4
Seriously Fish species profiles 1671.8

Maximum recorded length. Measured as total length. Fish in home aquariums often stay smaller than wild records.

Water temperature

Reported68–77°F
Seriously Fish species profiles 16768–77

Range the species tolerates; aim for the middle.

pH

Reported5.5–7.5
Seriously Fish species profiles 1675.5–7.5

Water hardness

Reported2–15dGH
Seriously Fish species profiles 1672–15

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 — pangio semicincta Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
  4. Seriously Fish — misgurnus anguillicaudatus 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.