Product Details

Pseudogastromyzon Ctenocephalus Loach – Gastromyzon ctenocephalus

The Pseudogastromyzon Ctenocephalus Loach is a specialist hillstream loach with a flattened body, strong sucker-like fins and a pattern designed for life in fast-flowing, oxygen-rich streams. More accurately listed as Gastromyzon ctenocephalus, this species is also known as the Blue Dorsal Borneo Sucker, Spiny-headed Hillstream Loach, Borneo Hillstream Loach or Ctenocephalus Sucker Loach. It is best suited to mature river-style aquariums with strong flow, high oxygen levels, smooth stones and natural biofilm growth.

Key Identification:

Common Name: Pseudogastromyzon Ctenocephalus Loach
Other Names: Blue Dorsal Borneo Sucker, Spiny-headed Hillstream Loach, Borneo Hillstream Loach, Ctenocephalus Sucker Loach
Scientific Name: Gastromyzon ctenocephalus
Older / Trade Name: Pseudogastromyzon ctenocephalus
Fish Type: Hillstream Loach / Sucker Loach
Water Type: Freshwater

Natural Range & Habitat:

Gastromyzon ctenocephalus is a Borneo hillstream loach associated with clear, fast-flowing upland streams and shallow rocky habitats. These environments are usually highly oxygenated, with smooth stones, gravel, exposed rock surfaces and strong current.

In the aquarium, this species needs a mature river-style setup with excellent oxygenation, clean water, strong flow and plenty of algae-covered stones. It should not be placed in newly set up aquariums, warm low-flow community tanks or soft decorative setups with poor surface movement.

Appearance & Adult Size:

This loach has the classic flattened hillstream body shape, with broad pectoral and pelvic fins that allow it to cling tightly to rocks, glass and wood in moving water. The body is usually dark brown, grey, olive or blackish with pale cream spotting or fine markings, and the dorsal area may show a bluish tone under suitable lighting.

Adults usually reach around 5–6 cm. Colour, spotting, fin tone and body pattern can vary between individuals, collection locality, mood and aquarium conditions.

Aquarium Suitability:

This is a specialist freshwater loach for mature, well-oxygenated aquariums. It is peaceful and fascinating to watch, but it has specific environmental needs and should not be treated as a general community “algae eater”.

The aquarium should be arranged with smooth river stones, rounded pebbles, driftwood, strong filtration and good water movement. Bright enough lighting to encourage natural algae and biofilm growth is useful, but shaded resting areas should also be available.

Recommended Aquarium Size:

A practical minimum is 75–90 litres for a small group, with a longer aquarium preferred over a tall one. Larger tanks of 120 litres or more are better for stable flow, oxygenation and group behaviour.

Keep in groups of 3 or more, with 5 or more preferred where space allows. Keeping them in groups encourages more natural behaviour and reduces stress, provided there is enough rockwork and grazing space.

Water Conditions:

Temperature: 20–24°C
pH: 6.5–7.8
Hardness: Soft to moderately hard water
Additional Notes: High oxygen levels and strong water movement are essential. Keep nitrate low and avoid warm, stagnant or poorly filtered aquariums. This species is not suitable for tropical tanks kept constantly at high temperatures. Mature biofilm growth on stones and wood is highly beneficial.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Pseudogastromyzon Ctenocephalus Loaches are peaceful and usually ignore other fish. They may lightly spar with each other over favourite stones, but this is normally harmless if enough space and cover are provided.

Suitable tank mates include White Cloud Mountain Minnows, hillstream-suitable danios, peaceful rasboras that tolerate cooler flowing water, small gobies from similar habitats, other compatible hillstream loaches with care and peaceful freshwater shrimp only if breeding is not a priority. Avoid goldfish, large cichlids, warm-water discus, angelfish, slow gouramis, aggressive loaches, fin-nippers and any fish that requires still, warm or low-oxygen water.

Feeding:

This species grazes on biofilm, soft algae, aufwuchs and tiny food particles from stones and hard surfaces. Natural grazing should be supported with a mature aquarium and algae-covered rocks.

Offer sinking algae wafers, spirulina tablets, gel foods, blanched courgette, cucumber, spinach, Repashy-style aufwuchs foods and fine sinking pellets. Occasional frozen foods such as daphnia, cyclops or brineshrimp can be offered, but the diet should remain rich in plant-based and biofilm-style foods. Do not rely on aquarium algae alone.

Behaviour in the Aquarium:

This loach spends much of its time attached to stones, glass or wood, grazing surfaces with short movements. It may move quickly between rocks and often chooses areas with good current.

When settled, individuals can become surprisingly visible, especially around feeding time or on favourite grazing stones. They may rest flat against surfaces and use their broad fins to hold position against flow.

Care Notes:

Provide strong aeration, excellent filtration and regular water changes. A river manifold, powerhead, spray bar or additional flow pump can help create the water movement this species prefers.

Avoid sharp gravel, dirty substrate, low oxygen and high temperatures. Make sure food reaches the bottom and that faster midwater fish do not take everything first. Do not add to immature aquariums with no established biofilm. Stable water quality is more important than chasing extreme parameters.

Recommended For:

Intermediate freshwater aquarists

Availability:

Occasional / Specialist freshwater import

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, body tone, pale spotting, blue dorsal tone, fin shape, body pattern and markings can occur between individual fish.