Botia dario – Bengal Loach

Botia dario – Bengal Loach

Botia dario was first described by Hamilton in 1822. The genus name”Botia” refers to the genus of Indian mudskippers, a group of bottom-dwelling freshwater fish. The species name “dario” is specific to this particular species within the genus Botia. The exact etymology of”dario” is not readily ascertainable. Their common name is Bengal Loach.

Botia dario belongs to the family Botiidae (or Cobitidae, depending on the taxonomic classification used ). The family Botiidae includes several species of mudskippers, which are characterized by their elongated bodies, bottom-dwelling lifestyle and often striking colors.

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

Appearance, Behavior and Life Expectancy

Botia dario has an elongated, cylindrical body, slightly flattened on the underside. The head is relatively small and rounded, with a prominent upward curve. The flanks are yellow to golden yellow in color, with 7 to 9 vertical brown or black bands. Between these bands are often thinner, lighter stripes. However, color and pattern can vary between individuals. The fins are usually pale yellow to transparent, sometimes with a slight tan tinge. Botia dario has six pairs of bearded threads around the mouth and two sharp spines under the eyes, characteristic of the Botiidae family. In the wild they can grow up to 15 centimeters long, but in aquariums they usually stay smaller, around 7 centimeters.

Sex differences: females are generally fuller-bodied than males. Behavioral differences during reproduction are described (see Chapter 3), but general behavioral differences between the sexes are not evident.

Juveniles vs. Adults: Young Botia dario are smaller and their colors are less pronounced than in adult specimens. The bands on their bodies may be less distinct or even completely absent in very young fish. As they age, they develop their characteristic yellow color and banding pattern.

Behavior and Temperament: The Botia dario is a social fish that prefers to be kept in groups of at least six. Lonely individuals can become stressed and more susceptible to disease. They tend to be shy during the day and like to hide in hiding places, but become more active at dusk and at night. They are bottom dwellers that like to burrow in the bottom in search of food. They are generally peaceful, but can exhibit aggressive behavior toward smaller fish if they feel threatened or if kept alone. They are not suitable tank mates for cichlids.

Life expectancy: The life expectancy of Botia dario in the wild is unknown. In an aquarium, they can live about 8 years.

Habitat and Ecology

Botia dario is native to Bangladesh, India and Myanmar. In India, they are found in the Brahmaputra and Ganges river basins, and in the north of the country. They live in rivers and streams, such as the Brahmaputra, Ganges, and the Ataran (Salween basin).

Their natural habitat consists of fast-flowing rivers and streams with rocky or gravelly bottoms. The waters are well oxygenated and there is often little underwater vegetation. The banks may be covered with trees and other river plants, but this is not always the case. The bottom consists of pebbles, gravel, and sometimes sand.

Botia dario lives in a tropical climate with a pronounced rainy season, leading to periods of flooding. During the dry season, water levels drop significantly.

Diet

Diet in the wild: Botia dario is an omnivore that has a varied diet in the wild . They feed on small invertebrates such as insect larvae, worms, crustaceans and snails. They also scrape algae from rocks and other surfaces.

Diet in the aquarium: In the aquarium, the Botia dario can be fed a varied diet consisting of live, frozen and dry food. Suitable options include: frozen food (e.g. tubifex, mosquito larvae), tablets, pellets and special food for Botias. It is important to offer a varied diet to ensure the fish get all the nutrients they need. Algae tablets can also be offered, as they also eat algae in the wild. It is important not to overfeed to avoid water pollution.

Aquarium and Care

A group of at least six Botia dario requires an aquarium of at least 100 liters, preferably larger. A larger aquarium (for example, 150 liters or more) is recommended, especially if you want to keep a larger group. The length of the aquarium is more important than the height or width, as these fish like to swim. An aquarium at least 80 centimeters in length is recommended .

The decoration should have a natural look with lots of hiding places. Use smooth, round stones, pebbles and pieces of wood to create hiding places. The Botia dario likes to burrow in the bottom, so a fine sand substrate is most suitable. Sharp gravel can damage the bearded threads. Plants can be added, but are not essential. Choose plants that can withstand the somewhat stronger currents these fish prefer. A subdued light is recommended, as they are shy during the day and like to hide. A tight-fitting lid is essential, as they can jump.

The ideal water conditions for Botia dario are a temperature between 23 and 26 degrees Celsius, a pH of 6.5 to 7 and a GH of 5 to 8. The water temperature should not change too quickly.

Compatibility: Botia dario can be kept well with other peace-loving, robust fish species that are not too small and do not have long fins. Suitable co-inhabitants include certain species of barbels, larger danios, algae eaters and garras. Avoid keeping with smaller fish, long-finned fish (such as guppies, cichlids and bettas), and slow-moving fish, as the Botia dario may intimidate them or damage their fins. Cichlids are definitely not suitable co-inhabitants. Keep in mind that Botia dario should preferably be kept in groups of at least six, preferably more .

Breeding

Botia dario is not easy to breed in an ordinary aquarium . Successful captive breeding has been described in a scientific article, but this was done in a controlled environment with specific equipment and procedures. The details of this breeding method are as follows:

• Breeding aquarium: Several experimental setups were used, including a special breeding aquarium with a diameter of 2 meters and a height of 0.5 meters, equipped with a flow system with adjustable water flow (1000 L/h and 5000 L/h).
  
• Water quality: Water quality was closely monitored and maintained within specific parameters: pH 7.5-8.5, total hardness 20-35 mg/l, specific conductivity 110-180 μS, total dissolved solids (TDS) 80-165 mg/l, and dissolved oxygen 7.6-8 mg/l. The temperature was maintained at 27-32°C .
  
• Lighting and filtration: Lighting and type of filtration are not specifically mentioned. However, the presence of a flow system suggests vigorous filtration to maintain water quality.
  
• Conditioning: The adult fish were conditioned with plankton , mosquito larvae, tubifex and commercially available fish food, given in an amount of 5-10% of their body weight per day.
  
• Sex ratio and mating: Five pairs(Botia dario) were used in the experiments (a ratio of 1:1). The males and females were not temporarily separated before breeding. The paper does describe mating behavior, in which the males chase and belly slap the females before depositing eggs.

It is important to note that this breeding method used synthetic hormones (WOVA-FH) to stimulate spawning behavior. This is a technique not suitable for hobbyists. So successful breeding of Botia dario in a home aquarium is not easy and requires a lot of experience and specific knowledge.

The Spawn

The natural spawning behavior is also described: During the mating season , the colors of the males become more intense. The yellow bands on their bodies become deeper in color. The courtship ritual begins with the males chasing the females. The males hit the females on their bellies with their heads, during which a cracking sound can be heard. Multiple males can chase a female at the same time, leading to fights between the males.

Spawning begins about half an hour after chasing begins. The eggs are deposited in flowing water. The experiments were conducted in various setups, including a special aquarium with a flow system. The eggs are scattered around. Spawning takes place at night.

The number of eggs ranged from 13,880 to 27,510 eggs per female. The eggs are non-sticky, whitish in color and transparent. The diameter of a fertilized egg is about 1 mm.

Raising the Young Fish

Based on the article on breeding Botia dario, we can say the following about the growth of the young fish: The eggs hatched after about 14.30 hours. The larvae began swimming and eating 21 hours after hatching. No parental care is described. The parents do not care for the eggs and newly hatched fish. Initial feeding consisted of Paramecium and later Artemia and small zooplankton. The survival rate of the young is not given in the article.

Particularities

Additional details about Botia dario:

• Noise production: Botia dario can produce a crunching sound with their throat, especially during feeding. This sound is caused by a special type of throat teeth they use to extract snails from their shells.
• Conservation Status: The IUCN classifies Botia dario as “Least Concern” (LC), meaning the species is not currently considered threatened. However, in Bangladesh the species does face threats from water pollution due to rice cultivation.
• Trade: Botia dario is traded in the aquarium trade, both live and dead (for consumption). The price varies depending on the location, availability and size of the fish.
• Taxonomic confusion: There has been considerable confusion around the taxonomy of Botia dario, with different synonyms and doubts about the validity of some related species such as Botia geto and Botia macrolineata.
• Captive breeding: Although captive breeding is possible, it requires a controlled environment and specific water parameters, often using synthetic hormones. Natural breeding is not easy in a home aquarium. The eggs are not sticky and are scattered around in running water. The larvae begin to swim and eat 21 hours after hatching.
• Distribution in Bangladesh: A study in Bangladesh found that Botia dario is most abundant in the Sunamgonj region, particularly in the Dekhar Haor and Brahmaputra rivers. Availability in the markets is highest from September to October.
• Aquarium Size: A group of at least six Botia dario requires an aquarium of at least 100 liters, preferably larger, with a length of at least 80 cm.

Conclusion

Botia dario is an attractive fish with a striking color pattern, but requires a specific approach in the aquarium. They are social fish that prefer to be kept in groups of at least six in a spacious aquarium (at least 100 liters, preferably larger) with a sandy bottom and plenty of hiding places. They are relatively easy to care for in terms of nutrition, but water parameters must be carefully monitored. Beginners would be better off choosing an easier fish species, as the Botia dario is sensitive to stress and needs a specific environment.

A notable feature is their nocturnal activity and shyness during the day, and their ability to produce a cracking sound. Although captive breeding is possible, it is a complex undertaking that is not suitable for beginners. Overall, they are interesting fish, but do require more experience and attention than many other aquarium fish. It is important to be well informed about their needs before purchasing them.

Video

Author

John de Lange

Copyright images

Emma Turner + Martin Thoene – Loaches.com

Bibliografie

The following is a bibliography of all the sources used to compile this profile of Botia dario. The dates refer to the date I consulted the information. Please note that some sources are web pages without author or publisher, and exact publication dates are not always available.

1. Wikipedia page on the genus Botia, accessed 22-03-2025.
2. Wikipedia page on Botia dario, accessed 22-03-2025.
3. Seriously Fish page about Botia dario, accessed 22-03-2025.
4. Fishkeeper page on Botia dario, accessed 22-03-2025.
5. Paul, S.K., et al. (2023). Distribution, abundance and status of Botia dario in the ornamental fish market, Bangladesh. International Journal of Environmental Research and Education, 3(2), 129-140. accessed 22-03-2025.
6. Dey, A., Sarkar, D., & Barat, S. (2015). Spawning biology, embryonic development and captive breeding of vulnerable loach Botia dario (Hamilton). Journal of Entomology and Zoology Studies, 3(6), 183-188., geraadpleegd op 22-03-2025.