Not furry, but we like them anyway.
Borneo Sucker Loach
Gastromyzon spp. (Günther, 1874)
Also called Borneo sucker, Gastromyzon, Butterfly loach (trade name, also used for other species), Hong Kong pleco (trade name, also used for other species)
From Endemic to the island of Borneo, where most species are restricted to one or a few river basins in fast hill streams.12
At a glance the quick version
Genus-level range from commonly traded species: G. ctenocephalus to 4 cm standard length, G. ocellatus to about 5 cm (2 in).
Looks how to spot one
Flattened hillstream loach
Small, flat and rounded from above, with wide fins that seal against stones like a suction pad. Colours vary by species; a typical traded fish such as G. ctenocephalus is dark with evenly spaced pale brown spots, creamy spots on the head and shimmering blue marks on the dorsal and tail fins. Females are a little larger and heavier.23
Personality what they are like
Peaceful toward other fish but mildly territorial with each other, holding favourite stones. In a group the small border disputes are part of their most interesting behaviour.23
Daily activity how busy a day looks
Busy daytime grazers that move over rocks facing into the current. They need fast, highly oxygenated water and plenty of grazing surface.23
Grooming and care the hands-on bits
Water: about 20 to 24 C, pH 6.0 to 7.5 (Loaches Online gives 7.0 to 8.0 for G. ocellatus), hardness 2 to 12 dGH. Oversized filtration and powerheads for a turnover of roughly 10 to 15 times the tank volume per hour, with frequent partial water changes.23
Home where they are happiest
A stream-style tank with a base of at least 60 x 30 cm (about 54 litres) for a small group, smooth pebbles and boulders, bright lighting for algae growth and strong current.23
Food basics what goes in the bowl
Mainly grazes algae and the tiny organisms living in it. Also accepts algae wafers, quality sinking foods, blanched greens and small frozen foods such as bloodworm, with plant-based foods forming the base.23
Company who they like around
Keep a group of four or more to see natural behaviour; some species even rest together in small loose groups. Best with calm fish that like cooler, fast water.23
The story where it all began
The genus was named by Albert Günther in 1874. Most of its roughly three dozen species were described only in the 2000s, largely through the work of Heok Hui Tan, which is why many aquarium fish are still sold under one loose name.1
Fun facts for the dinner table
- 1
Every Gastromyzon species is found only on Borneo, and many live in a single river basin.2
- 2
Several species look so alike that experts recognise pairs of near-identical lookalikes within the genus.2
- 3
In the wild they sit facing upstream in riffles near cascades, at elevations from sea level up to about 1,350 m.2
- 4
About 36 species are currently recognised in the genus.1
Recognised by the official bits
- Taxonomy
- Genus Gastromyzon, established by Günther in 1874 with G. borneensis as type species; about 36 species recognised, most described by H. H. Tan between 2003 and 20061
- Trade note
- The name Borneo sucker is applied loosely to several Gastromyzon species, which are hard to tell apart2
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Borneo Sucker 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.
- Wikipedia: Gastromyzon en.wikipedia.orgused for taxonomy, species count, history
- Seriously Fish: Gastromyzon ctenocephalus seriouslyfish.comused for representative care, size, behaviour, genus trade notes
- Loaches Online: Gastromyzon ocellatus loaches.comused for size, water parameters, diet, behaviour
Checked 2026-09-30. Text is written in our own words from these sources.