Quick Stats
| Adult Size | 20–30 cm (grow for years) |
| Minimum Tank | 75 gal juvenile; 120 gal+ (150 cm) adult group |
| Temperature | 25–30°C |
| pH Range | 6.0–7.5 |
| Hardness (GH) | 5–12 dGH |
| Difficulty | Medium |
| Temperament | Peaceful, social |
| Diet | Omnivore — sinking pellets, snails, frozen bloodworm |
| Schooling | 5+ required |
Tank Setup
The Clown Loach (Chromobotia macracanthus) is the sole member of its genus — a large, social, bottom-dwelling loach from the rivers of Sumatra and Borneo in Indonesia. The critical fact about this species is upfront: it is sold as a 5 cm juvenile and grows to 20–30 cm over several years, living 20+ years per the species' established reputation in the hobby (the site's own database says the same). A 75-gallon tank is the juvenile minimum; a mature group of five needs a 120-gallon-plus, 150 cm-plus footprint tank, and the wise buyer starts there.
Target 25–30°C — warmer than most community tanks run — with pH 6.0–7.5 and hardness 5–12 dGH. They are scaleless fish (technically, scaleless-ish: tiny embedded scales), which shapes both their substrate needs and their medication rules. Fine smooth sand is the right substrate — they root and dig for food with sensitive barbels, and rough gravel erodes them. Caves, driftwood tangles, and pipe clusters provide the dark hiding places a nocturnal-rooting fish needs by day; plant hardy species because juveniles dig.
The tank needs to be covered — clown loaches are reported jumpers in open-top tanks. Growth is bursty: they grow in stints and stall between them, which is normal, not a health problem. What is NOT normal is a stunted fish in an undersized tank — the species does not grow to its container, it just grows damaged.
Tank Mates
Clown Loaches are peaceful, social, and playful — famous for sleeping in piles, clicking audibly when excited, and lying flat on their sides (which alarms every new keeper who sees it; it is completely normal loach behaviour). They are mid-to-bottom dwellers that pose a threat to exactly one common aquarium group: snails. A group of clown loaches will methodically eliminate pest snail populations — which is why many people buy them, and why snail-eating is a behaviour to plan around rather than a feature to deploy casually (see the MTS profile for the one snail that survives them, thanks to its hard trapdoor and burrowing habit).
Good companions share warm water and peaceful temperaments: large tetras (adult rummy-nose and cardinal tetras (Paracheirodon axelrodi) share their temperature band), rainbowfish, pearl gouramis, angelfish in big tanks, and robust bottom partners like bristlenose plecos. Corydoras coexist, though they compete for sinking food; feed generously for both. Cherry shrimp (Neocaridina davidi) and Amano shrimp (Caridina multidentata) are safe with juveniles and at some risk from large adults.
Avoid anything aggressive enough to damage a scaleless fish (their lack of scales makes them vulnerable to bites and to medication — see Health), anything that needs cool water (goldfish (Carassius auratus) are a hard no — temperature and bioload both), and tank mate plans that depend on a resident snail population surviving. Within a proper warm, peaceful community, a mature clown loach group is the personality centrepiece of the tank.
Diet & Feeding
Clown Loaches are omnivorous foragers — snails, insect larvae, worms, and plant matter in the wild. In aquaria they take quality sinking pellets and wafers eagerly, plus frozen bloodworms, brine shrimp, and chopped market shrimp; they relish small snails and crush them with dedicated, noisy enthusiasm. The species' snail-hunting reputation is well-earned and makes them the classic biological control for pest-snail blooms (with the planning caveat above).
Feed sinking foods after lights-out — they are most active in the evening and overnight, and daytime feeding favours tank mates over them. They are slow, deliberate eaters that graze; pellets that reach the floor intact and frozen foods dropped near their caves get them their share. Juveniles in particular need daily protein feedings to grow through their early stunts.
Vegetables matter more for this species than for most fish: blanched zucchini and cucumber slices are consumed with real appetite, and a plant-matter fraction seems to reduce the barbel problems scaleless loaches are prone to. Vary the diet; clown loaches are intelligent enough to develop preferences and picky enough to act on them.
Common Health Issues
Clown Loach health has two governing rules, and both come from the same place — their scaleless skin. First, they are Ich-magnets: the most common clown loach disease in the hobby by a distance, usually after temperature swings. Second, they are medication-sensitive: standard full-dose ich treatments (malachite green formulations) can kill them outright. The correct approach is heat treatment — raising temperature slowly to 30°C over days — or half-dose medications explicitly labelled safe for scaleless fish (see the ich guide for the full heat-treatment protocol, and the medication dosing calculator for the arithmetic).
Barbel and skin damage are the chronic problems: rough gravel erodes barbels, sharp decor cuts scaleless skin, and both become infected. Sand substrate and smooth decor prevent nearly all of it. "Skinny disease" (internal parasites, often arriving with wild-caught stock) shows as a fish that eats but wastes — isolate and treat promptly; it spreads through groups.
And the behavioural alarms that are not diseases: clown loaches sleep on their sides in caves (normal), click their pharyngeal teeth audibly when feeding or excited (normal), and grey-out or "grey out" temporarily when stressed or establishing (normal if brief). A keeper who has read this paragraph diagnoses half their clown loach "problems" as behaviour.
Breeding
Clown loaches do not breed in home aquaria. Commercial availability depends on hormone-assisted spawning in Indonesian and Malaysian fish farms, and despite decades of attempts by advanced hobbyists, natural captive spawning is essentially unrecorded in typical home tanks. Sexing is possible in adults (mature females are visibly deeper-bodied, males develop longer tail-fin streamers), but it changes nothing practical for the home keeper.
The reason matters for planning: because all stock is farm-raised, juveniles arrive with the usual farm-batch disease exposure (ich, skinny disease), so quarantine is genuinely important for this species even though it is expensive and emotional to buy a group of five-plus at once.
The honest breeding section for clown loaches is therefore a purchasing section: buy the biggest juveniles you can afford from a healthy batch, quarantine them properly, and give them the 120-gallon-plus home they will grow into over the next decade. That is the entire successful husbandry of this species.
Frequently Asked Questions
How big do clown loaches actually get?
20–30 cm — around 30 cm in an appropriately large tank with years to grow. The 5 cm juveniles in shop tanks are months old; growth is slow and bursty but continuous for years. A single adult clown loach is roughly the mass of a small Oscar (Astronotus ocellatus). If the honest adult size does not fit your tank plans, consider the smaller botia species kept in the hobby instead of gambling on "it will stay small in my tank" — it will not.
Why is my clown loach lying on its side?
Almost certainly normal. Clown loaches famously sleep on their sides and backs in caves and under driftwood, in orientations that mimic a dead fish convincingly. Check for the sequence: fish that were fine at feeding time, now lie on their side in a favourite resting spot, and bolt upright when disturbed — that is clown loach rest. Actual sickness shows as clamped fins, colour loss, no feeding, and progressive weakness — a different picture entirely.
Do clown loaches eat snails?
Relentlessly. A group of clown loaches will methodically hunt and eliminate pond snails (Lymnaea stagnalis), ramshorns (Planorbella duryi), and similar pest snails — it is their most famous service behaviour. Malaysian trumpet snails (Melanoides tuberculata) survive substantially better thanks to hard trapdoors and deep burrowing. If you are buying clown loaches purely for snail control, consider first whether you can house a 30 cm, decades-long fish — snail-eating should be one happy side effect of a properly planned species choice, not the reason for it.
How many clown loaches should I keep?
At least five. They are strongly social fish that school, sleep in piles, and visibly stress as singles or pairs — a lone clown loach hides constantly and stops eating well. Five is the working minimum and eight-plus is the norm for display groups in 120-gallon-plus tanks. The group needs scale with the tank: no more juveniles than the adult sizes will eventually fit.