Cyprinids (Cyprinidae)

Green Labeo

Epalzeorhynchos frenatum

The striking fish with the scientific name Epalzeorhynchos frenatum, known as the Green Labeo, belongs to the family Cyprinidae. Its distinguishing feature is its vibrant green body coloration, which contrasts beautifully with its rich red fins. This species shares many characteristics with its closest relative, the Red-tailed Black Shark (Labeo bicolor), including its care requirements. Despite the extreme difficulty of breeding Green Labeos in home aquariums, they remain very popular among aquarists. All specimens available for sale are typically sourced from commercial fish farms in Thailand.

Tank
from 200 L (53 gal)
Temperature
22 – 26 °C (72 – 79 °F)
Size in aquarium
15 cm (5.9 in)
Acidity
pH 6.5–7.5
Natural rangeRange on the map
  • Mekong River Basin
  • Cambodia
  • Laos
  • Thailand

Tank conditions

Plan the tank stocking
Temperature
22 – 26 °C (72 – 79 °F)
Water pH
Neutral (6.5) – Neutral (7.5)
Water dH
Soft (5) – Hard (15)
Water salinity
no salt (freshwater)
Size in aquarium
15 cm (5.9 in)
Lifespan
15 years
Temperament
Territorial often aggressive
Toward small fish
not a predator
Required aquarium volume
from 200 L (53 gal)
Lighting
moderate (regular)
Substrate
fine sand
Water flow
moderate
Swimming level
near the bottom
Feeding
Meat with plant additives omnivores
Keeping
Solitary
Jumping
high a tight-fitting lid is essential
  • Lifespan. A lifespan to expect under good care, not a measured value: it depends heavily on tank volume, water quality and diet — and for selectively bred forms, on their origin as well.
  • Toward small fish. Based on the Predators category in the catalog or the temperament in the species parameters. “A risk to small fish” means the species is not a predator by habit, yet will swallow any fish that fits in its mouth.
  • Required aquarium volume. This is a husbandry recommendation, not a measured value: the volume depends on the keeping mode (solitary), footprint, decor and tank mates.

Care and keeping

Description

These fish have an elongated, graceful body shape. On the lower lip, there is a sucker equipped with horny plates, which helps scrape algae and organic deposits from various surfaces in the aquarium. The main body color is greenish, reminiscent of swampy hues, while the fins are brightly red. It should be noted that artificially bred color variations also exist.

Habitat

The natural habitats of these fish span Southeast Asia, including the territories of modern-day Thailand, Laos, and Cambodia. However, determining the precise size of their natural populations today is difficult. Habitat destruction caused by dam construction and the draining of wetlands has led to a significant reduction in the species' numbers, putting it at risk of extinction. Currently, all commercial trade relies on fish bred in artificial conditions. In their natural environment, they prefer small streams and rivers with sandy or rocky bottoms, and during the rainy season, they migrate to flooded areas of the forest floor.

Behavior and Compatibility

These fish prefer a solitary existence, and group formation is exclusively temporary, mainly associated with the spawning period. With age, the fish become increasingly territorial and aggressive. For the Green Labeo, an ideal solution is a species-specific aquarium designed for a single specimen. Its own kind and similar-looking fishes — gyrinocheilus, garra and algae eaters — get the worst of it: the labeo harasses them constantly, so only a single specimen is kept per aquarium. Loaches are usually left in peace.

Care and Maintenance

Like many fish whose lives unfold in flowing waters, the Green Labeo is very sensitive to water quality. Therefore, weekly water changes of 20–25% of the volume and siphoning the substrate to remove organic debris should become an integral part of their care. Regarding hydrochemical composition, the Green Labeo demonstrates remarkable adaptability, successfully tolerating a wide range of pH and dH values. To ensure optimal living conditions, it is recommended to install a powerful filter, an aerator, a heater, and a lighting system. In aquarium decor, preference is given to a gravel substrate with several large boulders, as well as various shelters created from driftwood, roots, and tree branches. With good lighting, wooden elements become an excellent basis for algae growth, which serves as an additional source of natural food. As for plants, any species with a well-developed root system will be suitable.

Diet

In natural conditions, the diet of these fish consists of plant detritus and algae, to which they incidentally add small crustaceans, insect larvae, and other aquatic life inhabiting plants. In an aquarium environment, it is important to provide a regular and varied diet, including both live or frozen foods (Daphnia, Artemia, bloodworms) and high-quality dry food mixes (granules, flakes). In addition, vegetable supplements are essential. Aquarists often use shelled peas, zucchini or cucumber, spinach, lettuce leaves, and pieces of fruit. These vegetable foods should be submerged to the bottom of the aquarium, using ties or rubber bands for anchoring. They should be refreshed every 2–3 days to prevent decomposition.

Breeding and Reproduction

Achieving reproduction of these fish in a home aquarium is practically impossible. This process is handled by specialized fish farms, which use hormonal preparations for commercial breeding.

Diseases

When favorable living conditions are maintained, health problems usually do not arise in these fish. Diseases most often manifest due to deteriorating conditions, an inadequate diet, or contact with infected individuals. It should be noted that some hereditary diseases may be inherent in artificially bred color variations, such as the Albino Red-tailed Black Shark.

How to choose

When choosing a Green Labeo, attention should be paid to the fish's activity and the condition of its skin. A healthy specimen should have a bright, rich coloration, clean fins without signs of damage, white film, or erosions. Avoid purchasing fish with sunken bellies, signs of emaciation, or unnatural behavior, such as lethargy, constant hovering near the surface, or attempts to hide in the corner of the aquarium when a person approaches. Since the species is highly territorial, fish in stores are often under stress, which can temporarily suppress their aggression. It is recommended to purchase young specimens, as they adapt more easily to new conditions and get along better with tankmates in a community aquarium. Before purchasing, ensure that the fish shows interest in food and actively responds to external stimuli.

Compatibility

There are no pair reviews for this species yet — check tankmates in the matcher.

All tankmates

Plants and this fish

Matching water does not mean the plant will stay intact.

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does Green Labeo get?

An adult reaches 15 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Green Labeo need?

The recommended volume is 200 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Green Labeo need?

Temperature 22–26 °C, pH 6.5–7.5, hardness 5–15 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Green Labeo live?

Around 15 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Green Labeo aggressive?

Temperament: territorial (often aggressive). Keep this in mind when choosing tank mates.

How many Green Labeo should be kept together?

Recommended setup: solitary. Ignoring this is a common cause of stress and disease.

What does Green Labeo eat?

Diet type: meat with plant additives (omnivores). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Green Labeo?

The scientific name of the species is Epalzeorhynchos frenatum, family Cyprinids (Cyprinidae). It also appears in the literature as: Epalzeorhynchus frenatus, Labeo erythrurus, Labeo frenatus.

Similar fishes

Matched by family, categories and overlapping keeping conditions

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Other scientific names and conservation status

Other scientific names
Epalzeorhynchus frenatus, Labeo erythrurus, Labeo frenatus
Categories
Cyprinids