Clown loach

Clown loach
Conservation status
Not Evaluated
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cypriniformes
Family:	Botiidae[1]
Genus:	Chromobotia Kottelat, 2004
Species:	C. macracanthus
Binomial name
Chromobotia macracanthus (Bleeker, 1852)
Synonyms
Botia macracantha

The clown loach (also tiger botia),^[2] Chromobotia macracanthus, is a tropical freshwater fish belonging to the botiid loach family. It is the sole member of the Chromobotia genus. It originates in inland waters in Indonesia on the islands of Sumatra and Borneo. It is a popular fish in the freshwater aquarium trade and is sold worldwide.^[3]

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.^[4] In 2004, Dr. Maurice Kottelat divided the Botia genus, containing 47 different species, into seven separate genera, resulting in the clown loach being placed in a genus of its own, Chromobotia.^[5]

The genus Chromobotia derives its name from the Greek word chromo, meaning "colour", and the regional Asian word botia, meaning "warrior" or "soldier"; the specific epithet Macracanthus is derived from the Greek word macros, meaning "large" and the Latin word acanthus, meaning "thorny", referring to the large spine below each of the fish's eyes. The common name, "clown loach" comes from the fish's bright colors and stripes (many 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

Clown loach in an aquarium

Information about the maximum size of the clown loach varies, with some estimates ranging up to 40–50 cm (16–20 in), and with typical adult sizes ranging from 15–20 cm (5.9–7.9 in).^[6] 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.

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. There is some regional color variation within the species; the pelvic fins on fish from Borneo are reddish orange and black, while the pelvic fins on fish from Sumatra are entirely reddish orange.^[7]

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.^[4]

The fish has a movable spine that lies in a groove below the eye, which may be extended as a defense 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 Sumatra 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.^[2] Breeding adults migrate to smaller waterways to spawn annually.^[6]

In its native habitat, the fish is found in water with a temperature range of 25 to 30 °C (77 to 86 °F), a pH between 5.0 and 8.0, and water hardness between 5 and 12 dH.^[3]

In the aquarium

A harmless, very active and sociable fish, clown loaches are best kept in groups of 5-6 or more. Due to their potentially large size, a 75 to 120 gallon (283 to 454 litre) aquarium should be the minimum size used.

These fish have bifurcated subocular (located under the eyes) spines, which are used as a defense mechanism and for obtaining prey. If a loach deploys its spines while caught in a net, untangling it is difficult and can result in injury to the handler or the fish. Aquarists recommend that large specimens are double or triple bagged, or placed in a solid container when being moved.

When kept in groups smaller than five, clown loaches may spend lots of time hiding under obstacles in the water. Tiger barbs and panda corydoras associate happily with clown loaches, and the three species may school together.

Clown loaches make clicking noises when they are excited or during feeding. This sound is produced by the grinding of their pharyngeal teeth. Sometimes clown loaches swim on their sides, or upside down, and appear ill, or lie on their sides on the bottom of the tank and appear to be dead. This is normal behaviour so the aquarist should be aware of it to avoid removing healthy fish from the aquarium.

If clown loaches do not come out of hiding, there are some easy things to adjust so that they will be more comfortable. A good tank set-up for a clown loach should include ample shade, real plants, hiding places and other peaceful fishes.^[8] Make sure the environment is not too bright initially. Provide shade from tank lighting. The tank should not be next to a window unless ample shade is provided. Window tanks with ample sun will allow Chromobotia to warm themselves and do their dominant color dances with more splendor as they flash in and out of sunlight slicing through openings in natural cover. An example tank will have a powerhead to create a current for them to swim against as well as cover to stay under while doing so as in a mountain brook of clear water with current rushing down between boulders. In fact, clowns show a strong preference for larger rocks taken directly from mountain streams too swift to allow algae growth. They will peck at these rocks often and always sleep under and on them.

Clown loaches are keen observers of other fish in the aquarium; they observe and react accordingly. If other fish are skittish and hide, clowns will observe this and do the same. Make sure that other fish in your community tank are docile and not prone to hide. Chromobatia will all sleep together under anything they can fit under in your aquarium.

Because clown loaches come from rivers and streams, they are accustomed to having other fishes and plants in their environment. Not having plants and/or other fishes can cause clown loaches to become stressed and to go into hiding. Especially on introduction to a new tank, it is important that lots of placid, active smaller fish are present. Until you know what fish company they like best, use many colors and varieties of inexpensive minnows. Another important thing to remember is that since they do come from a fast moving river environment, they need a tank with lots of clear, well filtered and fast moving water which can be achieved with proper filtration and the use of powerheads. Stream rocks should allow resting back eddies as well as shade and cover.

Two juvenile clown loaches with ich. Characteristically, for this stage of infestation, both are hiding in an ornament.

Before introducing clown loaches to your tank, make sure the fish you currently have are compatible because aggressive fish will stress your clown loaches and may need to be removed. Clown loaches are particularly susceptible to Ichthyophthirius (ich),or white spot disease, so they must be watched closely when initially introducing them to a tank and when new fish are added. Due to having small or no scales at all, a reduced dosage may be required when using certain types of medication, possibly reducing the effectiveness.

A variety of food should be provided for clown loaches, and their behaviour should be observed during feeding. In a community tank other fish may take the food before it reaches the bottom, where the clown loaches normally feed. However, with a tank supported with natural environments, clowns are very noisy surface feeders who will assert themselves to take the most and the best of bloodworm. 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 worms, especially if it is fortified) and frozen brine shrimp (always thaw frozen food to aquarium temperature).

See also

• List of freshwater aquarium fish species

Wikimedia Commons has media related to Botia macracanthus.

Videos and links

• Video of clown loaches

• Care information for the clown loach at the Aquarium Wiki
• Chromobotia macracanthus
• Chromobotia macracanthus - Atlas El alquimista de los acuarios
• Clown Loaches Community - Clown loaches Facebook page
• Clown Loaches Group - Clown loaches Facebook group

References