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 Furry Diary remembers it for you
A typical home-care rhythm for a Dwarf Chain Loach. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- 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
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.
- 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.