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Botia dario

by Mark in Vancouver last modified Dec 13, 2006 10:04 PM


Botia dario

Scientific name: Botia dario (Hamilton, 1822)

Common name: Queen Loach, Bengal Loach, Geto Loach.

Synonyms: Botia geto, Cobitis dario, Cobitis geto, Canthophrys flavicauda, Diacanthus flavicauda, Canthophrys zebra, Diacanthus zebra.

Distribution: India, Bangladesh.

Sexual Dimorphism: Unknown. Females probably plumper.

Maximum size: 6 inches. (15cm)

Similar to: None.

Care: Bengals are very social loaches. Numerous shelters should be provided which gives them the feeling of greater security and generally makes them bolder. Like most bottom-dwellers the substrate should consist of a fine-grained or round-edged gravel. In common with other scaleless or small-scaled fish, they are susceptible to ich and other skin parasites. When treating, be sure to check the directions on your choice of cure and follow the directions for scaleless fish.

Feeding: Omnivorous; will readily take both commercially prepared foods and live/frozen foods.

Water parameters: pH:6.8-7.5. Hardness:Soft to medium. Max dh:12.0.

Temperature: 75ºF to 82ºF(24-28°C)

Breeding: Not known to breed in the aquarium.


Botia darioBotia dario are found wild in the rolling mountain streams of Bangladesh. This country is situated just south of the Himalayas, and is criss-crossed with streams that feed three main rivers. These streams irrigate crops grown on the hillsides before draining into the Bay of Bengal, and the primary crops are rice and jute.

Pesticides used in the cultivation of rice have contaminated many streams and waterways in Bangladesh, and threaten Botia dario. Since 1997, the Bengal government has enforced strict penalties against polluters, with specific rules about the pollution of streams and waterways, so at least some preservation work is afoot.

Bangladesh is a damp, damp place. Most regions of the country receive over a meter of rain in a year, and the hilly northern sections can expect as much as five meters (15 feet!) of rain. This falls primarily during monsoon season, when all the water in the country rises to such a level that land normally used to grow rice becomes a series of shallow lakes in which to fish for food. (And, presumably, the aquarium market).

Botia darioIn January, at the coolest time of the year, air temperatures drop to around 26C, but in the spring temperatures average in the 35C (96F) range. Beyond the abundant supply of rain, a constant flow of glacial and snow melt-water makes its way down from the Himalayas to feed the thousands of streams.

This multitude of streams feed the Meghna and Jamuna rivers, which converge with the end of the Ganges, as it drains and forms a delta which comprises most of the populated land in Bangladesh. The amount of water that drains through the deltas of coastal Bangladesh is second only to the outflow of the Amazon.

B. dario can be found in the creeks and streams of the northern and eastern regions of the country (bordering India and Myanmar, respectively), and is also known in India. The fish most likely populates the streams that supply the Bengal section of the Ganges river. B. dario are also reported in Bhutan, but only in the Gaylegphug river, which eventually drains into the far north of Bangladesh.

This fish belongs to Bangladesh, so the name "Bengal Loach" is, then, quite appropriate.

Bangladesh is also the home to lots of other loaches, including Botia ("BOU MACH" in Bengali), Acanthobitis, Lepidocephalichthys, Nemacheilus, and five species of Schistura.

According to the statisticians and loving ichthyologists at, the Bengal Loach will eat 30.6 times its body weight in food each year. They can grow up to six inches in the wild, and perhaps in a large tank, but like most loaches, aquariums may stunt their natural growth.

In the tank, they're mostly bottom grazers. I have mine in a 20 gallon planted tank with a number of silver-tip tetras. I'm using an Aquaclear HOB filter and an extra 301 power-head/canister filter for current. 78F/25C water temps... PH: 6.8, weekly 40% water changes, vacuuming, etc...

Botia darioWatching a small group of Botia dario is good sport. Most of their time is spent gravel-grazing, as they search for crumbs of food beneath the particles of substrate. They tend to swim with their noses in the gravel, at an angle of about 30 degrees. I believe them to be more active in this constant search for food than Clown Loaches - who seem to grow accustomed to feeding times, and less dependent on scavenging.

Bengals are very social loaches, and physical with one another to the point of jostling and frequent nipping. They will tussle over food and hiding spots, but they don't injure one another. When offered Hikari sinking wafers - either the carnivore ones or the algae wafers - they will actually drag the wafers off in their mouths, and snap at the others if they come too close. In this way, they behave remarkably like dogs: food is paramount.

Despite their sometimes rough competitions over food, one gets the impression that (like a lot of loach behavior), these skirmishes are important to them socially. A hierarchy is established in a short time with these fishes, and I would suggest that keeping one of them at a time in your tank would be unwise, if not unkind. Perhaps they can learn to socialize with other Botia species.

Like most loaches and other river-dwelling fish, the cleaner the water that you keep them in, the better they will do. They come from streams after all.

Botia darioMeals that will thrill a Bengal Loach includes flake food, sinking wafers, (thawed) frozen bloodworms or brine shrimp, and they really like cucumber slices. These meals are accompanied by loud clicking sounds common to Botia.

Given a thin slice of zucchini, regular cucumber, and the seedless "English" cucumber, at the same time each night, my Bengals went for the seedless cucumber every time out of ten. I cut a quarter inch slice of each vegetable, ran it under warm tap water for a moment, so it wouldn't be cold, shook off the tapwater, pierced it with a regular bamboo cooking skewer, and then pinned it into my gravel substrate.

Each evening experiment showed the same results: Out of four B. dario in my tank, one is clearly dominant, and is more territorial (and greedy) than the others. The seedless cucumber is preferred by all of them, but the dominant loach, or "alpha dario," will actually sit on top of the food and defend it, either by pushing the other dario away with a kind of body-check move, or he'll nip at them.

Despite the presence of the other vegetable offerings in the tank, the remaining three loaches try to grab bites of the cucumber that has been claimed.... to the point that the alpha loach spends more time defending than eating. The dario will pick at boiled, skinned peas, but not with as much zeal.

People have remarked on how shy their Bengals seem to be, but I have seen nothing shy about mine. Primarily focused on the bottom of the tank during the day, they can often be seen scouring the upper stretches of the plants in the evening, swimming quite capably near the surface and in the middle zone. At night two or three might huddle together in a tight cave, or rest in the open.

Botia darioWhat's more, they can be seen at night to perform a very slow version of the "loachy dance," where one or a group of them will swim in large loops against the glass of the aquarium. I have read that the females are bulkier than the males in this species, but when they're well fed, this becomes a challenge to verify.

That's it. If you find Botia dario - the Bengal loach - available, and you have enough room in your tanks to offer them, pick them up! They're very entertaining and energetic fishes, as attractive and interesting as nearly any other loach, and unique in their own right. When you bring them home, think about the distant nation of Bangladesh, where each and every B. dario in the trade comes from.

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