Double Blue Zebra Borneo Loach - Gastromyzon sp.

Product Details

Double Blue Zebra Borneo Loach – Gastromyzon sp.

The Double Blue Zebra Borneo Loach, Gastromyzon sp., is a specialist hillstream loach with a flattened, suction-adapted body and attractive striped or zebra-like markings. Also sold as a Borneo Sucker Loach, Zebra Borneo Loach, Butterfly Loach or Hillstream Loach, this is a peaceful but demanding freshwater fish for aquariums designed around fast-flowing, oxygen-rich water. It is best chosen for a mature river-style setup with smooth stones, bright lighting, natural biofilm and cooler tropical conditions rather than a typical warm community tank.

Key Identification:
Common Name: Double Blue Zebra Borneo Loach
Other Names: Zebra Borneo Loach, Blue Zebra Borneo Sucker, Borneo Sucker Loach, Butterfly Loach, Hillstream Loach
Scientific Name: Gastromyzon sp.
Fish Type: Hillstream Loach / Borneo Sucker Loach
Water Type: Freshwater

Natural Range & Habitat:
Gastromyzon loaches are native to Borneo, where they live in shallow, fast-moving streams and hill rivers. These habitats are usually clear, highly oxygenated and filled with smooth stones, cobbles, bedrock and submerged roots. Instead of living in still water, they cling to surfaces in current and graze on biofilm, soft algae and tiny invertebrates. The Double Blue Zebra form should therefore be kept as a specialist Borneo hillstream fish, even though the exact species name is not confirmed.

Appearance & Adult Size:
This loach has a broad, flattened body with enlarged pectoral and pelvic fins that work almost like a suction pad, helping it grip rocks and glass. The body is typically brown, grey, olive or dark-toned with contrasting stripes, bands, spots or zebra-like patterning. Depending on the import and individual fish, blue-toned highlights may be visible around the tail or fins, especially under good lighting and when the fish is settled. Adults usually reach around 4–6 cm.

Aquarium Suitability:
The Double Blue Zebra Borneo Loach is best suited to a mature river-style aquarium with strong water movement, excellent oxygenation and a large surface area of smooth rocks for grazing. It can work in a peaceful specialist community, but it is not suitable for warm, stagnant or newly set-up aquariums. A bright-lit aquascape with rounded river stones, open flow zones, patches of algae and biofilm, and shaded resting areas will suit it far better than a heavily stocked tropical community tank with low circulation.

Recommended Aquarium Size:
A practical minimum aquarium size is around 90 litres for a small group, with a tank length of at least 90 cm preferred. Larger aquariums are recommended for multiple hillstream loaches or active tank mates that also enjoy current.

Water Conditions:
Temperature: 20–24°C
pH: 6.5–7.5
Hardness: Soft to moderately hard
Additional Notes: High oxygen levels are essential. Provide moderate to strong flow from an external filter, powerhead or river-style setup. Keep nitrate low, avoid stagnant areas and do not keep this fish at consistently high tropical temperatures.

Temperament & Tank Mates:
Aquarium Category: Community Fish

Double Blue Zebra Borneo Loaches are peaceful with most other fish, but they may gently chase or push each other away from favourite rocks and grazing areas. They are best kept in groups of three to five or more, provided the aquarium has enough hardscape and feeding space. Suitable tank mates include White Cloud Mountain Minnows, small danios, peaceful rasboras, small stream-suitable barbs, hillstream gobies and other calm fish that enjoy clean, well-oxygenated water. Avoid goldfish, large predators, aggressive loaches, very warm-water species, delicate long-finned fish and slow tank mates that dislike strong flow.

Feeding:
This species is a natural grazer, feeding on biofilm, soft algae, diatoms and small microorganisms from rock surfaces. In the aquarium, it should be offered algae wafers, spirulina foods, specialist gel foods, sinking micro pellets and fine catfish foods. Supplement with small frozen or live foods such as daphnia, cyclops, brineshrimp and occasional bloodworm. Blanched courgette, spinach or kale may also be accepted. It should not be added to sterile new aquariums where no grazing film has developed.

Behaviour in the Aquarium:
This is a bottom and surface-clinging fish rather than a free-swimming loach. It will graze across smooth stones, glass, wood and broad leaves, often choosing high-flow areas near filter outlets. It may dart quickly between surfaces, rest flat against rocks and defend small feeding spots from other loaches. In a well-designed tank with good flow and plenty of grazing surfaces, it becomes active, visible and fascinating to watch.

Care Notes:
A mature aquarium is essential. Provide strong flow, high oxygenation, smooth stones and steady access to biofilm-based food. Avoid sharp décor, dirty substrate, low oxygen and high temperatures. Make sure prepared foods actually reach the loaches, especially in tanks with faster midwater fish. This fish is not a general-purpose algae cleaner and should only be kept by aquarists who can provide proper hillstream conditions.

Recommended For:
Intermediate to experienced

Availability:
Rare to occasional; usually wild-caught or imported under specialist Borneo hillstream loach trade names.

Image Disclaimer:
All images are a visual representation of the fish you will receive, made to be as accurate as possible. Natural variation in size, colour, pattern and markings can occur between individual fish.