The Dwarf Chain Loach is considered to be the best all around aquarium fish of Botia type loaches!

The Dwarf Loach or Chain Loach Yasuhikotakia sidthimunki is one of the most attractive Botia type loaches. Previously it was scientifically described as Botia sidthimunki. It has a pretty golden to white coloring accented with a nice bold chain-type patterning that extends along the entire length of the upper half of its body.

This Chained Loach is considered to be the smallest of its genus, reaching only 2 to 2 1/2 inches (5 – 6 cm) in length. It has been a popular fish and all sorts of common names are associated with it. They are derived from both its appearance and its interesting behaviors, as well as its scientific names. You can find it called Dwarf Chain Loach, Dwarf Botia, Monkey Botia, Chained Loach, Ladderback Loach, Pygmy Loach, Mouse Loach, Chipmunk Botia, Sid, and Sid Monkey Loach.

This is a very active, yet peaceful fish. A small group of Dwarf Loach makes an attractive addition to a community aquarium. They enjoy the company of their own species and will do best in a group of six to eight, three is considered the minimum. These loaches are not as shy of light as many of its cousins, and will be active and playful during the day. For a comfortable home provide a soft substrate, some rocks and roots, and some plants for resting places. The water should be soft with regular changes. They are easy to care for in a well maintained aquarium and will eat any type of food that is provided, especially enjoying live and frozen worms.

Dams constructed on their natural river system caused a lot of habitat destruction, so wild caught specimens are extremely rare. These fish are commercially produced today, but are not often readily available and can be expensive. Its close cousin The Black-Lined LoachYasuhikotakia nigrolineata is very similar in both appearance and behavior, and can be a good substitution.

Scientific Classification


Dwarf Loach – Quick Aquarium Care

Aquarist Experience Level:Intermediate
Aquarium Hardiness:Moderately hardy
Minimum Tank Size:20 gal (76 L)
Size of fish – inches2.4 inches (5.99 cm)
Temperature:76.0 to 82.0° F (24.4 to 27.8&deg C)

Habitat: Distribution / Background

The Dwarf Loach or Chained Loach Yasuhikotakia sidthimunki, (previously Botia sidthimunki) described by Klausewitz in 1959. It is found in northern India and Thailand. This loach is basically restricted to the Mae Klong river basin in Western Thailand and the Ataran drainage on the boarder between Thailand and Myanmar.

This species is listed on the IUCN Red List as Endangered (EN). This is mainly due to the construction of hydroelectric dams in the 1980’s and 1990’s. Their habitat was covered by reservoirs. They are no longer present in habitats downstream in the on the Mae Klong nor in the reservoirs, but are present in parts of streams above reservoirs. Other threats are pollution from land development for agricultural and in the past from over fishing for the aquarium trade. The Thai government keeps much of the localities secret for conservation purposes.

This species is considered to be the smallest of its genus. They live in sections of the river that are shaded by the forest and it feeds on aquatic invertebrates. The waters have a slow to moderate flow with sand and rock substrates.

  • Scientific Name: Ambastaia sidthimunki
  • Social Grouping: Groups
  • IUCN Red List: EN – Endangered


The Dwarf Chain Loach is a small fish, reaching between 2 – 2 1/2 inches (5 – 6 cm) in length. They generally have a life span of about 8 – 12 years, though it has been reported to have lived up to 15 years.

This loach has a stripe running laterally along the side from its nose to its tail. Its body is whitish below the middle stripe while above the stripe are golden blotches separated by dark markings. Then there’s another dark stripe close to the top, giving it a ‘chained’ appearance. These chain markings show up when the fish is about 1 1/4″ in size but is most intense while it is a juvenile. As an adult these chain-like markings fade. The intensity of the stripe can also change with its mood, varying from a dark heavy stripe to extremely light stripe that can be almost invisible. The tail is a light yellow.

  • Size of fish – inches: 2.4 inches (5.99 cm) – These fish generally reach from 2 – 2 1/2 inches (5 – 6 cm).
  • Lifespan: 15 years – Their life span is usually about 8 – 12 years though reportedly specimens have lived up to 15 years.

Fish Keeping Difficulty

This loach can be hardy under the right conditions. They are not recommended for beginners because of their need for pristine water and having small body scales. Reduced scales makes them more prone to disease and very sensitive to medications used to treat disease. Experience in treating scaleless fish is very important to be able to give your loach a healthy and long life. Do not try to introduce these fish into biologically immature tanks.

  • Aquarium Hardiness: Moderately hardy
  • Aquarist Experience Level: Intermediate

Foods and Feeding

Since they are omnivorous, the Dwarf Loach is not a picky eater. In nature this loach feeds primarily on aquatic invertebrates, but in the aquarium it will generally eat all kinds of live foods, sinking pelleted and tablet foods, flakes, and algae. They like frozen foods as well. To keep a good balance give them a high quality flake or tablet food everyday. Feed mosquito larvae and brine shrimp (either live or frozen), tubifex, daphnia, and some vegetable foods such as algae wafers.

  • Diet Type: Omnivore
  • Flake Food: Yes
  • Tablet / Pellet: Yes
  • Live foods (fishes, shrimps, worms): Some of Diet
  • Vegetable Food: Some of Diet
  • Meaty Food: Most of Diet
  • Feeding Frequency: Several feedings per day

Aquarium Care

The most important thing for these loaches is that they always have clean and well-oxygenated water. Frequent water changes of about 30% a week are needed. With your weekly water change make sure to vacuum the gravel to remove all excess food and waste. Make sure not to remove the biofilm on rocks, decor or no viewing panes of the tank. A magnet algae cleaner normally does a great job in keeping the viewing pane clear.

  • Water Changes: Weekly – Water changes of about 30% weekly.

Aquarium Setup

Unlike most of it genus which are bottom dwellers, the Dwarf Chain Loach will also swim in the middle of the aquarium. Because these fish do best in groups, a tank of at least 20 gallons or more is needed.They do best in soft, slightly acidic water with low to moderate lighting.

Never introduce this loach into a biological immature setup as these fish require pristine water. They do best in soft, slightly acidic water with subdued lighting. They also need good water movement that provides plenty of oxygenation. The tank should turnover at least 10-15 times per hour, powerheads and airstones can be introduced to achieve proper flow and oxygenation. An undergravel filter is a great choice for these fish as it creates high oxygen through out the tank as well as reducing the waste.

The decor with this fish is really up to personal taste as the fish doesn’t really pay much attention to it. If the tank is to resemble its natural habitat, sand and gravel mix would be best for the substrate. Plants are nice as are rocks and roots to give them a places to rest. Some smooth water-worn large rocks and stones can also be scattered throughout. These loaches are very inquisitive and like to explore so make sure to have a lot of caves and crevices. These fish can and will jump out of the tank if given the chance so make sure to have a tight fitting cover.

  • Minimum Tank Size: 20 gal (76 L)
  • Suitable for Nano Tank: Yes
  • Substrate Type: Sand/Gravel Mix
  • Lighting Needs: Low – subdued lighting
  • Temperature: 76.0 to 82.0° F (24.4 to 27.8&deg C)
  • Range ph: 6.5-6.9
  • Hardness Range: 1 – 15 dGH
  • Brackish: No
  • Water Movement: Moderate
  • Water Region: Middle – Unlike most of its genus, which are primarily bottom dwellers, this fish tends to also swim in the middle of the aquarium.

Social Behaviors

These loaches make good community fish as they don’t demonstrate the nipping tendencies of some of their cousins. This being said it is still not advised to keep slow swimming long-finned fish with them and slow moving bottom dwellers. They are happiest when kept in a school of their own kind. A group of six to eight is suggested, with a minimum of three. They are also not as timid when it is light and are active and playful during the day.

  • Venomous: No
  • Temperament: Peaceful
  • Compatible with:
    • Same species – conspecifics: Yes – Best in groups of 6 or more, with a minimum of 3.
    • Peaceful fish (): Safe – Safe with fish that stay in the middle to upper parts of the tank. Can be nippy with slower bottom fish.
    • Semi-Aggressive (): Monitor
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • Monitor
    • Shrimps, Crabs, Snails: Threat – is aggressive
    • Plants: Monitor – Can be nippy with slow swimming long-finned fish and slower bottom fish.

Sexual differences

Sexually mature females are normally fuller-bodied and grow a little larger than males, while adult males develop slightly elongated snouts plus noticeably fleshy, thickened lips.

Breeding / Reproduction

Most of the Dwarf Chain Loaches that have been sold in the hobby in the past 10 years or so were produced by the use of hormone injection spawning in Thailand. The breeder specimens used for the first attempts had to be purchased from private collections because wild fish were so rare. Since then, some new wild populations have been found so new breeders have been collected.

  • Ease of Breeding: Difficult

Fish Diseases

Loaches are more susceptible to disease than other aquarium fishes. This may have to do with the faint body scales and no head scales. So take caution when introducing the Black-Lined Loach to an established tank. They are also very sensitive to different medications used to treat many diseases; a separate hospital tank is needed. Cold water and condition changes can also cause stress to this fish which makes them even more prone to disease.

Most common disease that affects this loach is Ich. Ich is short for Ichthyophthirius, also known as “white spot disease”. It is a parasite that can attack nearly all aquarium fishes, but you’ll find that loaches are often the first to be attacked. Take great care in treating ick as loaches are very sensitive to the medications used to treat it. Often the dose is half of what is normally used.

The second most common thing that affects loaches is a thing called skinny disease. This can be diagnosed fairly easily. If your loaches are eating a nitrous and healthy amounts and still seems to loose weight it is a good chance it has skinny disease. This is caused by internal parasites and can be treated with medication if used carefully.

An outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. When keeping these sensitive types of fish, it is common to catch deteriorating water conditions and disease before other fish are affected. The best way to proactively prevent disease is to give your Dwarf Chain Loach the proper environment and give them a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. A stressed fish will is more likely to acquire disease.

Anything you add to your tank can bring disease to your tank. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so not to upset the balance. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.


The Dwarf Loach or Chained Loach use to be readily available to the hobbyist but has become quite rare in recent years. This is mainly due to the construction of hydroelectric dams. Their habitat was covered by reservoirs.
However some new wild populations have been found and collected for captive breeding. There are captive bred specimens, but they are not always readily available and can be expensive. Its close cousin, the Black-Lined Loach, is more readily available and can be a good substitution.



Featured Image Credit: Oksana_Schmidt, Shutterstock