Not furry, but we like them anyway.
Dwarf Chain Loach
Ambastaia sidthimunki (Klausewitz, 1959)
Also called Dwarf loach, Dwarf botia, Chain loach, Chain botia, Ladderback loach
From Western Thailand (Mae Klong basin, including the Khwae Noi River) and the Ataran river on the Thailand-Myanmar border. Older Mekong records are now thought to refer to the related Ambastaia nigrolineata.123
At a glance the quick version
Looks how to spot one
Tiny, slender botiid loach
The smallest of the botiid loaches, a little torpedo-shaped fish with barbels and tiny spines under the eyes. Females grow larger and fuller-bodied, while mature males develop a longer snout and thicker lips.14
Personality what they are like
Sociable and busy. Unlike most loaches they are active in daylight and often shoal a little above the bottom. They click, chase and mimic one another, and are generally good in calm community tanks, though very slow or long-finned fish are best avoided.134
Daily activity how busy a day looks
Lively and active throughout the day, swimming in loose groups in the lower and middle water and joining in excited group swimming at feeding time or after water changes.134
Grooming and care the hands-on bits
Fit a tight lid because they can jump. Use sand or smooth gravel, plenty of plants, rocks and wood, and keep water clean and stable. Buy captive-bred fish, which are widely farmed.12
Home where they are happiest
A base of at least 80 x 30 cm (about 72 litres). Temperature about 20 to 30 °C (most sources suggest 25 to 28 °C), pH about 5.5 to 7.5, hardness about 1 to 12 dGH.132
Food basics what goes in the bowl
Mostly carnivorous but will nibble plant matter. Offer small sinking foods plus frozen or live bloodworm, daphnia and brine shrimp, with occasional vegetables. They readily eat small snails.12
Company who they like around
A shoaling fish: keep at least 5, ideally 10 or more. Good companions are small peaceful fish such as rasboras, small barbs and other gentle bottom dwellers.14
The story where it all began
Wolfgang Klausewitz described this tiny loach in 1959 from Thailand. Wild stocks became scarce and the fish vanished from the hobby for several years before the year 2000, but Thai farms now breed it in large numbers, which keeps it available to fishkeepers without relying on the wild.124
Fun facts for the dinner table
- 1
At around 6 cm it is the smallest member of the botiid loach group.4
- 2
Unlike most loaches it is active by day and often swims in open water rather than staying on the bottom.3
- 3
It was once thought to be extinct in the wild until fish were found again near Sangkhla Buri in Thailand.2
- 4
Fish farms have bred it for more than three decades, supplying the aquarium trade.2
- 5
Its exact Thai collecting sites are kept secret to help protect the wild populations.1
Recognised by the official bits
- IUCN Red List
- Endangered (assessed February 2011); also protected in Thailand3
- Taxonomy
- Family Botiidae. Described by Wolfgang Klausewitz in 1959 as Botia sidthimunki, later moved to Yasuhikotakia and then to Ambastaia. The species name may honour Aree Sidthimunk of the Thai Department of Fisheries.1
The care rhythm a typical week and year
A typical home-care rhythm for a Dwarf Chain Loach. A starting point, not a vet's advice.
- FeedingSmall amounts once or twice a dayevery day
- Temperature checkevery day
- Water changeAbout 25% of the waterevery week
- Water testevery week
- Glass cleanevery week
- Filter rinseRinse in old tank water, never tap waterevery month
Owner questions the things everyone asks
How often should I feed my Dwarf Chain Loach?
Feed small amounts once or twice a day. Furry Diary's starting plan suggests daily feeding, but always check the food label and ask your vet for exact portions.12 Pet Wiki plan
What does a Dwarf Chain Loach eat, and what should it never eat?
They are mostly carnivorous and enjoy small sinking foods, frozen or live bloodworm, daphnia, brine shrimp, and occasional vegetables. They also eat small snails. Never feed them anything not listed here; ask your vet for a safe diet.12
How much space does a Dwarf Chain Loach need?
A tank base of at least 80 x 30 cm (about 72 litres) is recommended. They are active swimmers and need room to shoal.132
What temperature, light or water does a Dwarf Chain Loach need?
Keep water temperature around 25 to 28 °C, pH 5.5 to 7.5, and hardness 1 to 12 dGH. Use sand or smooth gravel with plants, rocks, and wood. A tight lid is essential as they can jump.132
How often should I clean a Dwarf Chain Loach's home?
Furry Diary's plan suggests a 25% water change weekly, along with weekly glass cleaning and water testing. Rinse the filter monthly in old tank water, never tap water. Pet Wiki plan
Can a Dwarf Chain Loach live with others?
Yes, they are sociable and should be kept in groups of at least 5, ideally 10 or more. Good tank mates include small peaceful fish like rasboras and small barbs, but avoid very slow or long-finned fish.14
How long does a Dwarf Chain Loach live?
Lifespan varies; ask your vet or a good breeder for specific information based on your fish's care.
Can I handle a Dwarf Chain Loach?
It's best not to handle them. They are delicate and have tiny spines under their eyes. Use a net only when necessary, and always keep them in water.14
Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.
Where this comes from
Every fact on this page has a numbered source. Spotted an error? [email protected].
- Seriously Fish: Ambastaia sidthimunki seriouslyfish.comused for origin, size, tank and water, diet, behaviour, dimorphism, taxonomy, history
- Wikipedia: Ambastaia sidthimunki en.wikipedia.orgused for other names, range, rediscovery, farming, protection
- FishBase: Ambastaia sidthimunki summary fishbase.seused for length, environment, IUCN status, daytime shoaling
- Loaches Online: Yasuhikotakia sidthimunki loaches.comused for smallest botiid, behaviour, group size
Checked 2026-09-30. Text is written in our own words from these sources.