Clown Loach Care Guide

The clown loach is the hobby's most mis-sold fish — a peaceful, gentle, playful giant that is sold as a cute 5 cm juvenile and grows into a 30 cm (12 in) loach that lives 20 to 30 years and needs a six-foot tank and a real group. Its calm temperament fools buyers into treating it as a beginner community fish; the size, the decades-long commitment, the scaleless ich-prone body and the invert-predator mouth make it nothing of the sort.

Clown Loach at a glance

The sourced figures the welfare engine uses to judge Clown Loach — the parseable key facts.

Where it comes from

It is endemic to Indonesia — the rivers of Sumatra and Borneo (the Kapuas, Kayan, Batang Hari, Musi and Tulang Bawang systems). Crucially it is a seasonal blackwater/floodplain fish, the opposite of the cool hill-stream yoyo: adults live in main river channels but ride the wet-season flood pulse upstream into flooded riparian forest, slow, soft, seasonally acidic water dense with leaf litter and submerged wood. Every care decision falls out of that origin. The warm tropical floodplain means it wants genuinely warm water (28 to 30 degrees is preferred, not merely tolerated). The soft, acidic blackwater means it is at home down to pH 5 to 6 and should never be forced into hard alkaline water. The leaf litter and crevices mean it is a cave-dweller that wants abundant driftwood and tight hides to squeeze into. And the soft floodplain bed means sand or fine smooth gravel to protect the barbels and scaleless belly. The seasonal spawning migration is also why it effectively cannot be bred at home.

Did you know?

• It lives for decades — possibly the longest-lived common community fish, routinely passing 20 years with documented hobby specimens at 28 to 30-plus. The aquarium "20-year fish" is real.
• It gets its own genus — the sole species in Chromobotia, split out of Botia by Maurice Kottelat in 2004.
• It's a snail-cracking machine that clicks — it produces audible clicking, likely from grinding pharyngeal teeth or the sub-ocular spines, which gets louder when the fish are excited.
• It plays dead — clown loaches habitually rest on their sides, upside-down or wedged at odd angles, alarming-looking but completely normal botiid resting behaviour.
• It has switchblades under its eyes — erectable sub-ocular spines flick out when stressed or netted, snagging nets, so move it in a container, not a net.
• It changes colour with its mood, "greying out" as its bold pattern fades during dominance battles.
• Its two wild populations, from Borneo and Sumatra, diverged around 9.5 million years ago, with Bornean fish reportedly larger.
• It migrates upstream to spawn on the rainy-season flood — which is exactly why it can't be bred at home. IUCN lists it as Least Concern.

Tank size — and why

A 125 US gallon tank is the practical floor for a small group, and a six-foot (180 cm) footprint is the real target — Seriously Fish calls 180 by 60 cm the absolute minimum to house a group. The driver is not bioload alone but adult size times group size times sheer activity: a group of six 30 cm loaches needs serious floor area and length to spread out, establish a hierarchy and do the restless "loachy dance", so a long, low tank beats a tall one every time. The trap is the slow growth — it takes several years to approach full size, which is exactly why buyers under-buy tank space for the tiny fish in front of them. Plan the tank for a 30 cm active loach from day one; the small "captive" fish people quote are usually stunted, not adult, and stunting is the species' number-one killer.

As a guide, a 125-gallon tank comfortably suits a starter group of about 6 Clown Loach. As floor-dwelling shoalers they want bottom area, not water column, so a bigger group or added tankmates pushes you toward a larger footprint rather than fitting in alongside.

How big does it really get?

Full-grown Clown Loach reach about 30 cm (11.8 in) long, but they are usually sold at only about 6 cm (2.4 in) — a typical shop size (estimate). At full size, Clown Loach needs roughly a 125-gallon tank, about 183 cm long; a common 10-gallon starter kit is only about 51 cm.

Adult size is sourced; the shop size is a typical-juvenile estimate; tank length is approximate for a standard 125-gallon aquarium.

Water parameters in practice

Warm, soft and slightly acidic, and above all stable. Target 27 to 30 degrees — and unlike most loaches, 30 degrees here is a legitimate preferred warm temperature, not a stressful extreme. That warmth is also the front-line ich treatment (the gentle-heat method to roughly 30 degrees), convenient because the species likes that heat anyway. Aim for pH around 6.0 to 7.0; FishBase allows a wide 5.0 to 8.0 envelope, and the fish tolerates neutral, but it is a soft-acidic blackwater fish at heart and must not be pushed into hard alkaline water. As a scaleless botiid it is very sensitive to ammonia, nitrite, dissolved toxins and unstable water — it is "intolerant to accumulation of organic wastes" and needs a mature, fully cycled tank with weekly 30 to 50 per cent water changes. It is a classic first casualty of a new, immature setup.

Will it thrive in your water?

The comfortable range for Clown Loach is about 25–30 °C (77–86 °F) and pH 6–7.5. Test your own tap water against it below.

These are the sourced comfortable ranges. Stable water matters more than chasing an exact number — a steady reading inside the band beats a "perfect" one that drifts. Some fish also need a particular water hardness (GH); where that applies, the prose above covers it.

Diet & feeding

In the wild it is a carnivore-leaning omnivore and benthic forager taking molluscs, insects, worms and other invertebrates, plus some soft plant matter. Aquatic snails are squarely on that menu, which is why it is a renowned pest-snail predator that will happily clear a snail outbreak. The honest caveat from Seriously Fish is the same as for the yoyo: it should never be considered the answer to an infestation, because it is not an obligate molluscivore — effective, but not a magic cure, and it still needs a proper varied diet. Feed sinking foods that reach the bottom: quality sinking pellets, algae wafers, gel/Repashy-type food, supplemented with frozen or live bloodworm, Tubifex and brine shrimp, plus blanched vegetables (cucumber, courgette, spinach) which should make up a meaningful share of the diet. It is an assertive, competitive feeder that out-competes slower bottom dwellers, so feed small amounts once or twice a day and do not overfeed.

Gear & setup

Heater required — this is a genuinely warm-water tropical fish (27 to 30 degrees), the opposite of the coldwater dojo. Use sand or fine smooth gravel, never sharp or coarse gravel, which erodes the barbels (sensory feeding organs) and abrades the scaleless belly. Provide abundant caves, driftwood, rockwork and tight crevices — more hides than fish — because they wedge into gaps to rest and the hides protect subordinate fish from the group hierarchy. Keep lighting subdued and the water well-oxygenated, mature and stable with good flow and large weekly water changes. A tight-fitting lid is prudent: botiids probe for gaps and wedge into small spaces, so avoid décor with one-way traps that can trap a large loach.

Temperament & behaviour

Gentle, peaceful and playful toward other fish, but large, busy and boisterous enough that its sheer size and movement intimidate small or timid tankmates, and it may nip trailing fins. (FishBase tags it "Aggressive", an outlier that most likely reflects this boisterous activity and intra-group squabbling rather than true aggression.) Within a group it forms a ritualised hierarchy: "greying out" (the bold pattern fading dramatically during dominance battles), juveniles "shadowing" their elders flank-to-flank, the whole-group "loachy dance", sparring and audible clicking. It is diurnal-crepuscular and highly active when settled with cover and numbers, shy in a sparse or bright tank. Resting on its side or wedged at odd angles ("playing dead"), and heavy breathing after a burst of chasing, are completely normal — count and watch before you grieve.

Group & social needs

Intensely social and gregarious — it must never be kept alone. A lone or under-grouped clown loach becomes withdrawn, hides constantly, eats poorly and can turn on similarly-shaped fish. Keep six as the bare minimum (our corrected engine floor) and aim for six to ten or more; Aquarium Co-Op notes the most natural behaviour appears in groups of thirty-plus. Bigger groups are calmer and bolder, not rowdier, because the hierarchy spreads across many fish. The intraspecific squabbling is real but is solved by a bigger group and more hides, never by keeping fewer fish.

Compatible tank mates (preview)

A short, engine-cleared shortlist — the species TankStocking's welfare engine clears with Clown Loach and that suit its size and temperament best. Tap a name for its care guide, or use + to load the pairing in the planner.

• Moonlight Gourami+Peaceful temperament, similar adult size
• Scissortail Rasbora+Uses the midwater zone, peaceful temperament, similar adult size
• Snakeskin Gourami+Uses the midwater zone, peaceful temperament, similar adult size
• Boesemani Rainbowfish+Uses the midwater zone, peaceful temperament
• Bolivian Ram+Peaceful temperament
• Brilliant Rasbora+Uses the midwater zone, peaceful temperament
• Bristlenose Pleco+Peaceful temperament
• Clown Pleco+Peaceful temperament

This engine-cleared shortlist is Clown Loach's tankmate surface for now — a dedicated tank-mates guide can follow for high-demand species.

Breeding & sexing

Effectively impossible in the home aquarium — Seriously Fish notes private-hobbyist breeding "remains unheard of and undocumented". Wild spawning rides the rainy-season flood pulse upstream into fast-flowing rivers, cues that cannot be replicated in a tank, and Wikipedia notes captive reproduction occurs only after hormonal stimulation. All trade fish are wild-caught or farm-bred by hormone induction. Sexing is subtle and reliable only in mature fish: adult females are normally fuller-bodied and larger than comparably-aged males. Do not plan a breeding path.

Lifespan

A genuine decades-long commitment — typically 15 to 20-plus years with good care, with credibly documented hobby specimens at 20 to 30 years (fish bought in the 1990s still alive nearly three decades later). Treat 20 to 30 years as the realistic range; the often-quoted "up to 40 years" is older folklore that is rarely if ever verified. What shortens it: stunting in a too-small tank (the number-one killer); ich (it is the textbook ich-magnet and is also most likely to die from the treatment); overdosing copper, formalin or salt on its scaleless body; chronic poor or unstable water; sharp gravel; and the stress of being kept alone or under-grouped.

Common mistakes

• Underestimating adult size and lifespan — THE clown-loach trap. Sold tiny and slow-growing, it reaches ~30 cm and lives 20+ years. A 10 to 30 gallon nano tank stunts and slowly kills it. Plan a 125+ gallon / 6 ft tank and a 20-year commitment from day one.
• Keeping it with snails or dwarf shrimp. It is a deliberate snail predator that eats ornamental snails and preys on shrimp and shrimplets; buy it only if you specifically want a snail outbreak cleared, accepting the snails will go.
• Treating it as a beginner fish. Its gentle temperament fools buyers, but the size, decades-long lifespan, six-foot-tank and group needs, scaleless medication sensitivity and extreme ich susceptibility make it a clear intermediate-plus fish.
• Keeping too few, or just one. A lone or under-grouped clown loach becomes withdrawn, hides, eats poorly and can turn on similar-shaped fish. Keep six minimum, six to ten or more ideal, and remember a bigger group is calmer.
• Adding it to a new, uncycled tank. Scaleless and waste-intolerant, it needs a mature, stable, well-maintained tank and is a classic first casualty of an immature setup.
• Reaching for full-dose copper, formalin or salt at the first white spot. It is scaleless: use half-dose, scaleless-safe medications and the gentle-heat method to ~30 degrees.
• Sharp gravel substrate, which abrades the scaleless belly and erodes the barbels. Use sand or fine smooth gravel.
• Panicking over normal behaviour. Resting on its side, wedging at odd angles, clicking and heavy breathing after a chase are all normal.

Signs of trouble

• Staying hidden and off-food, or staying "greyed out" outside of normal dominance play.
• White spots — it is the textbook ich-magnet and usually the first fish in the tank to break out.
• Constant (rather than post-chase) heavy breathing or surface gasping — usually heat, low oxygen or a water-quality problem.
• Visible barbel erosion or belly abrasions, almost always a sharp-gravel injury and a route to infection.
• Clamped fins and loss of colour.
• A hollow belly or emaciation — "skinny disease", common in wild-caught stock; quarantine and deworm new arrivals.
• Being singled out and relentlessly chased — a sign the group is too small or there are too few hides.

Is this fish right for you?

Do not buy clown loaches if you keep ornamental snails or a dwarf-shrimp colony; if you can't provide a 125+ gallon / 6 ft tank and a group of six or more; if you can't commit for 20-plus years; if your tank is small, uncycled or coldwater; if you wanted a low-maintenance beginner or nano centrepiece; or if you keep very small fish a 30 cm loach could swallow. Most clown loaches are wild-caught or hormone-farmed and may arrive thin or parasitised, so buy active, well-coloured, non-emaciated fish with intact barbels and clear eyes, and quarantine and deworm them on arrival. There are no legitimate dyed or balloon morphs — avoid any painted or dyed specimens.

Bringing one home

Quarantine and ideally deworm new clown loaches on arrival — they are usually wild-caught or hormone-farmed and often turn up thin and parasitised, prone to "skinny disease" (treatable with Levamisole in the UK or Fenbendazole/Panacur in the US). Acclimate them gently to a mature, cycled, stable, warm tank, as scaleless botiids react badly to sudden swings in chemistry or temperature. Handle them with a container rather than a net, because the erectable sub-ocular spine snags in mesh.

Common questions

How big do clown loaches get and what tank do they need?

About 30 cm (12 in) for a well-kept adult — ignore the small "captive" sizes some shops quote, which reflect stunted fish. They grow slowly over years, so plan ahead: 125 gallons is the practical floor for a group and a 6 ft / 180 cm tank is the real target, with a long footprint preferred over height.

How long do clown loaches live?

Decades. Typically 15 to 20-plus years with good care, with credibly documented hobby specimens reaching 20 to 30 years. The "up to 40 years" figure is older folklore that is rarely verified. Stunting in a too-small tank is the number-one thing that cuts the lifespan short.

Can I keep clown loaches with snails or shrimp?

No. The clown loach is a deliberate pest-snail predator and will eat ornamental snails, and it harasses and preys on dwarf shrimp and shrimplets, increasingly as it grows. Treat snails and shrimp as incompatible — buy this fish only if you specifically want a snail outbreak cleared.

How many clown loaches should I keep?

Six is the bare minimum and six to ten or more is the real target — never keep just one. A lone or under-grouped clown loach becomes withdrawn, hides constantly and can turn on similar-shaped fish, while a bigger group is calmer and bolder because the hierarchy spreads across many fish.

Are clown loaches a good beginner fish?

No, despite being gentle and peaceful. The ~30 cm size, 20-plus-year lifespan, six-foot tank and group requirement, scaleless medication sensitivity and extreme ich susceptibility make it a clear intermediate-plus fish that is wrongly mis-sold as a beginner community fish.

Why is my clown loach lying on its side or clicking?

Both are normal. Resting on its side, upside-down or wedged at odd angles ("playing dead") is standard botiid behaviour, and clicking is the sound of its throat teeth or sub-ocular spines, louder when the fish are excited. Count your fish before assuming the worst.

Do clown loaches get ich, and how do I treat it?

Yes — the clown loach is the textbook ich-magnet and usually the first fish to break out, but as a scaleless fish it is also most likely to die from heavy-handed treatment. Use the gentle-heat method (raising to roughly 30 degrees, which it likes anyway) with half-dose, scaleless-safe medication; avoid full-dose copper or formalin.

Sources & confidence

Sources & confidence (9 species)

These back the Clown Loach figures and the previewed tank mates above. Each figure is read from the TankStocking species database (v2026.06); below is the care reference behind it and how confident we are in that data. Confidence reflects the source quality, not whether any pairing is safe. Full source list and the welfare model are on the methodology page.

• Clown Loach Chromobotia macracanthus — Seriously Fish (chromobotia-macracanthus) / Loaches Online high confidence
• Moonlight Gourami Trichopodus microlepis — Seriously Fish (seriouslyfish.com/species/trichopodus-microlepis) high confidence
• Scissortail Rasbora Rasbora trilineata — Seriously Fish (seriouslyfish.com/species/rasbora-trilineata) high confidence
• Snakeskin Gourami Trichopodus pectoralis — Seriously Fish (seriouslyfish.com/species/trichopodus-pectoralis) high confidence
• Boesemani Rainbowfish Melanotaenia boesemani — Seriously Fish; Aquarium Co-Op Boesemani guide high confidence
• Bolivian Ram Mikrogeophagus altispinosus — Seriously Fish (seriouslyfish.com/species/mikrogeophagus-altispinosus) high confidence
• Brilliant Rasbora Rasbora einthovenii — Seriously Fish (seriouslyfish.com/species/rasbora-einthovenii) high confidence
• Bristlenose Pleco Ancistrus sp. — Aquarium Source / aqua-fish.net Ancistrus care guides high confidence
• Clown Pleco Panaqolus maccus — Fish Laboratory (fishlaboratory.com/fish/clown-pleco); AquariumStoreDepot high confidence

Care-guide sources (6)

This guide synthesises the references below; where they disagree, the range and the disagreement are noted in the text above. The figures in the key-facts box are read from the TankStocking species database (v2026.06). Full welfare model on the methodology page.

• FishBase — Chromobotia macracanthus
• Seriously Fish — Chromobotia macracanthus
• Wikipedia — Clown loach
• Aquarium Co-Op — Clown Loach
• AquariumStoreDepot — Clown Loach Care Guide
• Fishkeeping World — Clown Loach Care Guide

More on Clown Loach

Related guides on TankStocking — each scored by the same welfare engine as the planner.

This care guide is a sourced planning reference, not veterinary advice — individual fish, filtration and maintenance all matter. Cycle the tank, test your water, and observe your fish. How TankStocking works →