At a glance the quick version
Seriously Fish gives 7.5 cm standard length; FishBase gives 8.0 cm total length.
Looks how to spot one
Flattened hillstream loach
Shaped a little like a tiny stingray: very flat and rounded when seen from above, with broad pectoral fins and pelvic fins joined into one large sucker disc that holds it fast to rocks. Females are broad and heavy-framed; males are slimmer with a squarer snout.1
Personality what they are like
Gentle and unhurried. Males claim small patches of rock, while females tend to gather where the current is strongest; squabbles are short and harmless.1
Daily activity how busy a day looks
Spends its day clinging to stones and glass and slowly grazing. It needs strong, well-oxygenated flow to feel at home; Seriously Fish recommends a turnover of 10 to 15 times the tank volume per hour.1
Grooming and care the hands-on bits
Water: 16 to 24 C, pH 6.5 to 8.0, hardness 2 to 15 dGH. Clean, clear, oxygen-rich water with strong flow, oversized filtration and regular partial water changes. A cooler subtropical fish that does not need heated water in most homes.1
Home where they are happiest
A stream-style tank with a base of at least 60 x 30 cm (about 54 litres), smooth rocks, pebbles and sand, bright light so biofilm grows, and powerheads for current. A tight lid is wise because these fish can climb glass.13
Food basics what goes in the bowl
Mainly grazes biofilm and algae with the tiny organisms living in it. In captivity it accepts sinking dried foods, vegetable-based preparations and small frozen foods such as bloodworm.1
Company who they like around
Found in loose groups in nature; Seriously Fish suggests buying six or more. Suits peaceful tankmates that enjoy cooler, fast-moving water.1
The story where it all began
Fang described the fish in 1931, at first as a form of Gastromyzon. It has since become one of the most widely kept hillstream loaches and is often sold under the trade name Hong Kong pleco, even though it is a loach rather than a catfish.1
Fun facts for the dinner table
- 1
Its pelvic fins are fused into one large suction cup, so it can stick firmly to rocks in fast water.1
- 2
It can literally climb up the aquarium glass.1
- 3
Despite the trade name Hong Kong pleco, it is a loach and not a member of the pleco catfish family.1
- 4
It is comfortable at room temperatures as low as about 16 C.1
Recognised by the official bits
- IUCN Red List
- Least Concern (assessed 28 April 2023)2
- Taxonomy
- Described by Fang in 1931, originally placed under Gastromyzon; a second subspecies, B. k. gracilicauda, is recognised from other river systems1
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Butterfly Hillstream 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 support@furrydiary.app and we will fix it.
- Seriously Fish: Beaufortia kweichowensis seriouslyfish.comused for names, range, size, care, behaviour, taxonomy
- FishBase: Beaufortia kweichowensis fishbase.seused for size, range, IUCN status
- Loaches Online species index loaches.comused for habitat cross-check
Checked 2026-09-30. Text is written in our own words from these sources.