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Clown Loach (Chromobotia macracanthus)

by Martin Thoene last modified Jan 05, 2013 10:48 AM




Scientific name:Chromobotia macracanthus (Bleeker, 1852)

Common name: Clown Loach

Synonyms: Botia macracantha, Cobitis macracanthus, Chromobotia macracanthus

Distribution: Malay peninsula, Borneo, Sumatra 

Sexual dimorphism: Mature fish deepen considerably and females tend to be bulkier. There are various theories about caudal fin lobe shapes being different, but these are inconclusive.

Maximum size: 16 inches

Similar to:



Chromobotia macracanthus




Care: This is a wonderful loach, but too large for most hobbyist aquariums. Allowed a minimum of 75 gallons or more, young Clown Loaches thrive in groups. They require large turnover, efficient filtration systems and current supplied by additional power-heads, frequent water-changes and great attention to cleanliness in the aquarium.

The tank should have subdued lighting, a soft, preferably sand substrate, and numerous hiding places provided made from rock-work or driftwood. Plants should be strong and resilient because large Clowns can be hard on them. They may uproot them, or punch holes in the leaves. Plant species must be capable of low-light environments.

Clowns are somewhat nocturanal in nature and often very lively in the early morning and after dusk. The addition of a blue moon light tube, or some other form of blue lighting, phased to come on before the main lights, and go off after them, will allow the owner to observe the fish at their most liveliest and entertaining. This will also avoid the fish being shocked by a sudden change in brightness.

Some people wish to keep Clown Loaches in aquaria housing Rift-Lake Cichlids. There are multiple reasons why this should not be done. See: Why Loaches Should Not Be Kept With Malawi Cichlids

Feeding: Defrosted frozen bloodworms, white mosquito larvae, brine shrimp, etc; chopped prawns are appreciated by larger fish; manufactured sinking wafers (algae, carnivore wafers...), fresh or blanched vegetables such as cucumber, zuchinni, lightly boiled peas. Other keepers have had success with foods such as watermelon and banana, quality flake food. Will enjoy nibbling at soft or fine leaved aquatic plants.

Water parameters: pH 6.5 - 7.0, Hardness: aim for softer water, Maximum DH: 12

Temperature: 78ºF to 87ºF (25-30°C)

Breeding: No confirmation of natural breeding in the aquarium. Some forced reproduction through the use of hormones on fish farms in the tropics is rumoured. It is known that they are raised by such methods in the Czech Republic.

See: Clown Loach Breeding




Chromobotia macracanthus, 8.5" and 10.5" fishClown Loaches are often sold at the very immature size of 1.5 inches (4cm) or so, but they should not be considered for the smaller (or even medium-sized) aquarium. They will grow quite rapidly from this cute size to around 5 inches (13cm), thereafter the growth slows somewhat, but with good care in a large tank, they can easily reach 8 to 12 inches (20 - 30 cm). They are big, bulky fish at that size. The two fish pictured were 8.5" and 10.5" body length when pictured. That is a standard foot rule beside them.

A potential owner should seriously consider the long-term commitment in purchasing a group of this species, as they will require ever- increasing size of aquaria and may potentially live at least twice as long as some small dogs.

Here are these two fish along with many smaller ones during feeding time

Adults will eventually require an aquarium measuring at least 6’ x 2’ x 2’. Even small specimens of this species must initially be housed in an aquarium that is 4ft long as a minimum. Anything smaller can cause these fast-swimming fish to become stunted and stressed.

Chromobotia macracanthus, sifting sand though gills. This fish, "Marge" is 11.5" long


This is "Marge". She's 11.5" (29cm) long and housed with nearly 50 other Clowns

They are regarded as a poor choice for the beginner aquarist despite their wide availability in fish shops. They are highly susceptible to Ich if great care is not given to their acclimation or environment maintenance. It is suggested that the aquarium be designed around their requirements specifically, rather than them being added to an unsuitable environment.

Chromobotia macracanthus group in a large tank


This huge aquarium houses nearly 50 Clowns including Marge. It is superbly maintained and has large filters and extra water movement provided by power-heads. This is how this species should be kept.


Due to their sensitivity to pollutants and nitrates, Clown Loaches are totally unsuitable for newly set up aquaria and should only be introduced to established, fully cycled tanks.

Quite frequently they are recommended to aquarists to help rid the tank of a snail infestation, but due to their large adult size, they are not always a suitable choice. Other smaller species of the genus Botia will also eat snails and would be considered a more appropriate choice for the smaller community aquarium.


Here is a 10.5 inch (27cm) long Clown with its bifurcated Suboccular spine raised.


Chromobotia macracanthus with Suboccular spines raised



Clowns raise these formidable weapons when they need to defend themselves, or when disturbed in some way. This one had recently been moved to this tank and was unsettled. Great care must be taken when moving Clowns and indeed all Botiine Loaches because the spines can catch in a net and damage the fish. Also, when transporting the species, multiple bags must be used to avoid punctures and loss of water.

Clown loaches are considered peaceful, and they make excellent additions to a large community tank if the focus of the tank is their needs first. They seldom bother even small fish and it is quite possible to have other species breed and the babies grow up un-predated by the Clowns.

Chromobotia macracanthus - A group engaged in "Loach-dancing"

Like many members of the genus Botia, this is a highly gregarious species with sophisticated social structures and some very odd behaviour.

They must be kept in groups. The absolute minimum recommendation is 5, but basically the more the merrier.

A group will establish a "pecking order" and there will be an Alpha Loach, most often a female, that will lead the group. At times, fights may break out and often lead to scratches and nicks on the fish because the suboccular spines may mark the other fish. In healthy fish in a well-maintained aquarium, these are of little consequence and will heal rapidly. During disputes, Clowns may change colour considerably, often much to the alarm of a new owner. See Clown Loach Coloration & Marking Variations.

Clowns will engage every so often in what we term "Loach-dancing" as depicted in the photo above. The whole group may tumble over one another in a vertically oriented, rotating group that will maintain this behaviour for quite a long time. Newly introduced groups of fish to an unfamiliar setting may act like this for a couple of days after introduction.

Another strange behaviour, common to most Botiine Loaches is the habit of sleeping in weird places and at weird attitudes. A new owner may be disturbed to find the fish laying on its side or upside down, often under some decor or in a cave structure. This is just Clowns being Clowns and it is partially their behaviour patterns that get them their common name. They are nothing if not entertaining.


Chromobotia macracanthus: Albert, the 17 year old clown loach.



Happiness is happy Clowns. They deserve the best.

Chromobotia macracanthus, Smilie Circle

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