The clown loach (''Chromobotia macracanthus''), or tiger botia, is a tropical

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

fish belonging to the

botiid Botiidae is a family of cypriniform ray-finned fishes from South, Southeast, and East Asia. Until recently they were placed in the true loach family Cobitidae, until Maurice Kottelat revised the loaches and re-elevated this taxon to family rank i ...

loach family. It is the sole member of the genus ''Chromobotia''. It originates in inland waters in Indonesia on the islands of

Sumatra Sumatra is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 473,481 km2 (182,812 mi.2), not including adjacent i ...

and Borneo. In Sentarum, West Borneo that fish named: ulanguli. It is a popular fish in the freshwater

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

trade and is sold worldwide.

Taxonomy and naming

The fish was first described as ''Cobitis macracanthus'' by Pieter Bleeker in 1852. In 1989, its scientific name was changed to ''Botia macracanthus''. In 2004, Dr. Maurice Kottelat divided the genus ''

Botia ''Botia'' (Indian loaches) is a genus of freshwater fish in the loach family (Botiidae). It was a large genus with about 20 species. In 2004 Maurice Kottelat proposed in his paper (along with the description of ''Botia kubotai'', see References b ...

'', containing 47 different species, into seven separate

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

, resulting in the clown loach being placed in a genus of its own, ''Chromobotia''. Its scientific name roughly translates to “Large-thorned colourful warrior”. The common name, "clown loach" comes from the fish's bright colours and stripes (often tropical fish with stripes that stand out are commonly called "clown") as well as from its habit of 'entertaining' aquarium owners with strange habits, such as swimming upside down, or 'playing dead.'

Description and behavior

Information about the maximum size of the clown loach varies, with some estimates ranging up to , and with typical adult sizes ranging from . The fish's body is long and laterally compressed, with an arched dorsal surface and a flat ventral surface. Its head is relatively large and its mouth faces downward with thick, fleshy lips, and four pairs of barbels. The barbels on the lower jaw are small and difficult to see. Clown loaches can make clicking sounds when they are happy, being territorial (used as a type of weapon/warning) or mating. This sound is produced by the grinding of their pharyngeal teeth. The body is whitish-orange to reddish-orange, with three thick, black, triangular, vertical bands. The anterior band runs from the top of the head and through the eye, the medial band lies between the head and the dorsal fin, and wraps around to the ventral surface, and the posterior band covers almost all of the caudal peduncle and extends to the

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

. There is some regional colour variation within the species; the pelvic fins on fish from Borneo are reddish-orange and black, while the pelvic fins on fish from

are entirely reddish-orange. The fish is sexually dimorphic, with females being slightly plumper than males. In addition, the tips of the tail on the male curve inwards slightly, whereas the females have straight tips. The fish has a movable spine that lies in a groove below the eye, which may be extended as a defence mechanism. The spine may cause a painful wound, but is not venomous. It also may be used as a predation tool as it is set close to the mouth.

Distribution and habitat

Clown loaches are native to the islands of

and Borneo in Indonesia. Clear stream environments provide the optimal habitat for clown loaches, but biannual monsoon flooding forces the fish to move into flooded flood plains, or murky or blackwater rivers or lakes, for 7–8 months of the year, and clown loaches are commonly found in the flood plains of hilly areas. Breeding adults migrate to smaller waterways to spawn annually. In its native habitat, the fish is found in water with a temperature range of , a pH between 5.0 and 8.0, and water hardness between 5 and 12 dH.

Reproduction in captivity

Clown loach reproduce in captivity only after hormonal stimulation of final oocyte maturation and ovulation. Captive breeding and mass production of clown loach is done primarily in country of origin (Indonesia) and in Europe ( https://www.youtube.com/watch?v=qerHElt1ozQ ).

In the aquarium

A common and popular fish for tropical freshwater aquaria, ''C. macracanthus'' is a visually pleasing species. Although specimens in the wild will reach 40 to 50 cm, in the aquaria it is uncommon for ''C. macracanthus'' to attain more than 15 to 20 cm fork length. They are a very long-lived species, living up to 30 years. These fish have bifurcated spines under the eyes. They are thought to be used as a defence mechanism and possibly, for obtaining prey. ''C. macracanthus'' will associate with other benthic species in the aquaria if kept singly or with few other specimens. They make suitable tank-mates for any non-aggressive community fishes, but do not thrive when kept with larger, more dominant species. Occasionally ''C. macracanthus'' will exhibit erratic swimming patterns, such as swimming on their sides or upside down. This is not usually a sign of illness, however, and the fish will normally return to normal behaviour almost instantly. As ''C. macracanthus'' is found in riverine environments it is able to cope with good flow rates of water in the aquaria. Aquascapes may replicate this environment to suit the requirements of the species with areas of high flow, but also typically include areas of low flow to allow the fish to rest. ''C. macracanthus'' is also fond of cover and is not overly accustomed to bright lighting. The fish will often seek areas of shade or cover in which to rest during the day and become more active when light levels are more subdued. The barbels of clown loaches are known to be easily damaged by rough substrates, such as gravel, in aquaria. Clown loaches are particularly susceptible to

Ichthyophthirius ''Ichthyophthirius multifiliis'', often termed "Ich", is a parasitic ciliate described by the French parasitologist Fouquet in 1876. Only one species is found in the genus which also gave name to the family. The name literally translates as "the ...

(ich), or white spot disease. Due to the fact that clown loaches have small or no scales, they are often not treated with full doses of medications. Over-exploitation of ''C. macracanthus'' has motivated the development of conservation efforts, mostly new artificial propagation techniques. ''C. macracanthus'' is easier to breed when individuals are between two and four centimeters in size. Most clown loaches accept commercial flake food and sinking pellets as their dietary staple, but thrive with a variety of food: live (worms, brine shrimp, small snails), banana, other plant matter, freeze-dried (

tubifex worm ''Tubifex'' is a cosmopolitan genus of tubificid annelids that inhabits the sediments of lakes, rivers and occasionally sewer lines. At least 13 species of ''Tubifex'' have been identified, with the exact number not certain, as the species ar ...

s, especially if it is fortified) and frozen brine shrimp. Clown loaches (and their cousins) are also one of the few fishes that will eat bladder snails ('' Physella acuta''), and are valued by aquarists for controlling this pest in planted aquaria.

References