Product Details

Green Laser Loach – Gastromyzon lepidogaster

Overview:

The Green Laser Loach is a specialist Borneo hillstream loach with a flattened body, powerful clinging fins and a striking green to metallic sheen in mature fish. Also sold as the Green Borneo Sucker or Neon Borneo Sucker, Gastromyzon lepidogaster is a fascinating algae and biofilm grazer for a mature river-style aquarium. It is peaceful, unusual and full of character, but it should not be treated as a general community algae eater; it needs cool, clean, fast-flowing, oxygen-rich water to thrive.

Key Identification:

Common Name: Green Laser Loach
Other Names: Green Borneo Sucker, Neon Borneo Sucker, Green Borneo Hillstream Loach, Borneo Sucker, Green Laser Hillstream Loach
Scientific Name: Gastromyzon lepidogaster
Fish Type: Hillstream Loach / Borneo Sucker
Water Type: Freshwater

Natural Range & Habitat:

The Green Laser Loach is native to northern Borneo, where FishBase records it from the Temburong River drainage. It is a freshwater hillstream species adapted to fast-flowing, shallow, highly oxygenated waters.

In nature, Gastromyzon species live on rocks, pebbles and submerged surfaces in riffles and stream channels, grazing on algae, biofilm and tiny organisms. In the aquarium, this habitat should be recreated with strong flow, smooth stones, mature grazing surfaces and excellent water quality.

Appearance & Adult Size:

Green Laser Loaches have a low, flattened body designed for life in current, with broad paired fins that help them grip rocks and glass. Colour can vary with age, mood, locality and condition, but mature fish may show dark base colour with reflective green, bronze or neon-like highlights. Some references note that Gastromyzon lepidogaster can change colour as it matures, with larger adults becoming bright green, orange or otherwise highly reflective.

Adults can reach around 8–10 cm, with FishBase listing a maximum of just over 10 cm standard length.

Aquarium Suitability:

This species is best for a dedicated hillstream, river-style or high-flow subtropical aquarium. It needs mature biofilm, rounded stones, cobbles, smooth wood, strong filtration and high oxygenation. Bright lighting can be useful to encourage natural algae growth, but shaded resting spots should also be included.

It is not suitable for warm, stagnant tropical tanks, newly set-up aquariums, soft muddy substrates or communities with large aggressive fish. Practical Fishkeeping notes that Gastromyzon loaches are best kept in cooler, well-oxygenated water rather than overheated aquariums.

Recommended Aquarium Size:

A practical minimum is 90 litres for a small group, with 120 litres or more preferred for better flow, oxygen stability and grazing space. A longer aquarium is better than a tall one, as these fish live on surfaces and benefit from a broad footprint.

Water Conditions:

Temperature: 20–24°C
pH: 6.5–7.5
Hardness: Soft to moderately hard; avoid unstable extremes
Additional Notes: Clean, highly oxygenated water is essential. Provide strong surface movement, a mature filter and additional flow from a powerhead or river manifold where appropriate. Seriously Fish recommends 18–24°C for general care of Gastromyzon lepidogaster and stresses that the water must be clean and well oxygenated.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Green Laser Loaches are peaceful, but they are specialist stream fish and should be kept with species that enjoy similar cool, oxygen-rich water. Suitable tank mates include White Cloud Mountain Minnows, small danios, hillstream loaches, Rhinogobius-type gobies, small peaceful barbs and other active stream species.

Avoid aggressive cichlids, large predators, warm-water community fish, slow delicate fish and boisterous bottom-dwellers that may block grazing areas. Keep in a group of at least 5 where space allows. Groups are more confident and show more natural interactions than single fish.

Feeding:

This species is a grazing omnivore with a strong need for algae, biofilm and aufwuchs. A mature aquarium with algae-coated stones is extremely beneficial. Supplement with algae wafers, spirulina foods, Repashy-style gel foods, fine sinking pellets, blanched vegetables and occasional small frozen foods such as daphnia, cyclops, brineshrimp or bloodworm.

Aquadiction notes that G. lepidogaster feeds naturally on benthic algae and microorganisms, and recommends algae-covered surfaces supported with dried, live, frozen and vegetable-based foods. Do not add this fish to a sterile new aquarium with no grazing surfaces.

Behaviour in the Aquarium:

Green Laser Loaches spend much of their time attached to stones, glass, wood or filter outlets, grazing and repositioning themselves in the current. They may gently spar over favoured rocks, but this is usually display behaviour rather than serious aggression. Their flattened body and suction-like fins allow them to cling tightly in strong flow, and they often choose the most oxygen-rich areas of the tank.

Care Notes:

This is a specialist hillstream loach for mature, high-oxygen aquariums. Strong flow, clean water and cooler temperatures are essential. Avoid hot tropical conditions, poor filtration and dirty substrates. Use smooth stones rather than sharp décor, and encourage algae growth before purchase. A secure lid is recommended, as hillstream loaches can climb glass and explore filter outlets.

Recommended For:

Intermediate to experienced

Availability:

Rare / Occasional / Specialist hillstream 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, colour, pattern and markings can occur between individual fish.