Product Details

Green Laser Loach – Gastromyzon lepidogaster

The Green Laser Loach is a specialist Borneo hillstream loach with a flattened body, powerful sucker-like grip and attractive greenish body patterning. Correctly known as Gastromyzon lepidogaster, this species is adapted to fast, oxygen-rich rocky streams and should be kept in a mature river-style aquarium rather than a standard warm tropical community tank. It is peaceful with suitable fish, but it needs strong oxygenation, clean water and established grazing surfaces.

Key Identification:

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

Natural Range & Habitat:

Gastromyzon lepidogaster is native to northern Borneo, where it is associated with freshwater hillstream and river habitats. These environments are typically fast-flowing, rocky, highly oxygenated and rich in biofilm, aufwuchs and fine algae growing across stones and hard surfaces.

In the aquarium, the Green Laser Loach should be provided with a mature river-style setup containing smooth stones, rounded cobbles, open grazing surfaces, strong filtration and high surface movement. This species should not be placed into newly set-up tanks, stagnant aquariums or layouts where all algae and biofilm are constantly removed.

Appearance & Adult Size:

Green Laser Loaches have a flattened, streamlined body adapted for clinging to rocks in strong current. The body is usually olive, greenish, brown-green or grey-green with fine patterning, giving the fish a subtle laser-like or neon sheen under aquarium lighting. Broad pectoral and pelvic fins help the fish hold position against water movement.

Adults can reach around 8–10 cm, making this a larger hillstream loach than some smaller Gastromyzon imports. Individual colour, pattern intensity and body tone can vary depending on age, mood, lighting and condition.

Aquarium Suitability:

This species is best suited to a mature hillstream aquarium, river-style aquascape or cool-to-moderate tropical community with excellent water movement. Provide smooth rocks, cobbles, wood, strong lighting to encourage natural grazing growth, and plenty of open surfaces for feeding and territorial display.

Green Laser Loaches are not suitable for brand-new aquariums, overheated discus-style tanks, low-flow setups, dirty substrates, low-oxygen aquariums or tanks where they must compete heavily for food.

Recommended Aquarium Size:

A practical minimum is 90–120 litres for a small group, with a tank length of at least 75–90 cm recommended. Larger aquariums are preferred because they provide more grazing area, stronger stable flow and more territories.

Footprint and surface area matter more than height. A long, shallow-style aquarium with strong circulation is better than a tall tank with limited rockwork.

Water Conditions:

Temperature: 18–24°C
pH: 6.5–7.8
Hardness: Soft to moderately hard
Additional Notes: High oxygen, clean water and stable conditions are essential. Maintain strong surface movement, good filtration and regular partial water changes. Avoid prolonged high temperatures, low oxygen, high nitrate and sudden parameter swings. This species can struggle in warm, slow-flow community aquariums.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Green Laser Loaches are peaceful towards suitable tank mates, but individuals may defend favourite grazing stones from other hillstream loaches. This is usually display behaviour rather than serious aggression when the aquarium has enough space, flow and feeding surfaces.

Suitable tank mates include White Cloud Mountain Minnows, small danios, peaceful rasboras, hillstream-suitable gobies, smaller barbs, Cory-type catfish in compatible temperatures, bristlenose plecs and other peaceful fish that enjoy clean, oxygen-rich water.

Avoid large predators, aggressive cichlids, goldfish, very warm-water species, slow long-finned fish in unsuitable flow, and boisterous bottom feeders that will outcompete them. Groups of 3 or more are recommended where space allows, with larger groups best in dedicated river-style aquariums.

Feeding:

Green Laser Loaches graze on biofilm, soft algae, aufwuchs and tiny invertebrates from rock and glass surfaces. They should not be expected to survive on algae alone. Offer sinking algae wafers, spirulina foods, specialist grazer pellets, soft gel foods, blanched courgette, spinach or other shrimp-safe vegetables, and occasional small frozen foods such as daphnia, cyclops, brineshrimp or bloodworm.

Feed in several places across the rockwork if keeping a group. In community aquariums, add food after lights dim or place it directly onto grazing stones so faster fish do not take everything first.

Behaviour in the Aquarium:

This species spends much of its time attached to rocks, glass, wood and décor, grazing in short movements across surfaces. In good conditions, Green Laser Loaches are active during the day and may display to one another over preferred feeding areas.

They are excellent climbers and can move up glass, filter outlets and hardscape. A secure lid and covered gaps are recommended. Confidence and activity improve in mature, well-oxygenated aquariums with plenty of grazing growth and minimal competition.

Care Notes:

Add Green Laser Loaches only to a fully cycled, established aquarium with visible biofilm or soft algae growth. Maintain strong flow, high oxygen and very clean water. Avoid copper-based medications unless confirmed safe for loaches, and never expose them to poor water quality or low oxygen.

Because this is a specialist hillstream species, it is best sold to customers who understand river-style aquarium care and can provide long-term grazing surfaces, not as a quick algae-control fish for a standard tropical tank.

Recommended For:

Intermediate

Availability:

Occasional / Specialist 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, green tone, pattern intensity, body shape and markings can occur between individual fish.