Epalzeorhynchos frenatum var.

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Epalzeorhynchos frenatum var., also called Albinos Rainbow Shark, is a very popular aquarium variety of the rainbow shark. Its pale coloration highlights the red fins and active bottom-dwelling shape. This albino form remains a territorial fish despite its peaceful-looking appearance, and it needs a well-structured layout to reduce confrontations. Native to Southeast Asia, it prefers clean, warm and well-oxygenated water. Common in the aquarium trade, it can be kept in a spacious community aquarium, provided that overly slow fish and species competing for exactly the same shelters are avoided.

General species description

Epalzeorhynchos frenatum var. is a depigmented variety of a Cyprinidae related to fish commonly called rainbow sharks. Despite its trade name, it is not a shark but an Asian cyprinid that spends much of its time near the bottom. It actively moves among roots, rocks and plants, then defends an area it considers its own. Keeping one individual is usually the simplest option; several fish require substantially more space and visual barriers. Its popularity comes from its elegant body shape, red caudal fin and lively behavior.

Geographical origin and biotope

Countries of reference: Thailand, Laos and Cambodia, in river basins associated with the Mekong and other waterways of the Indochinese Peninsula. In the wild, the species occurs in lowland streams with moderate flow, as well as quiet areas connected to rivers. The bottom is often made of sand, gravel and plant debris, with roots, branches and shoreline vegetation providing shelter. The water is generally warm and well oxygenated. In an aquarium, efficient filtration, moderate circulation and multiple hiding places recreate this setting more effectively than a completely open layout.

Precise location and local name

The species is associated with several basins of former Indochina, especially the Mekong basin and the Chao Phraya basin in Thailand. The trade name “Rainbow Shark” is widely used internationally; “Albinos Rainbow Shark” identifies the captive-bred variety presented here. This fish should not be confused with the red-tail shark, Epalzeorhynchos bicolor, which is a different species. Trade names can vary among suppliers, while the albino form is mainly recognized by its pale pinkish coloration.

Appearance and physical characteristics

The body is elongated and slightly compressed from side to side, with a short head and a downward-facing mouth suited to grazing surfaces. The albino variety has a cream, pale yellow or pinkish body, red or pink eyes, and fins that are often orange to bright red. The dorsal fin is well developed, while the caudal fin provides the strongest contrast. Adult size is usually around 12 cm, with a maximum close to 15 cm under good conditions. Its sturdy appearance and bottom-oriented posture are distinctive features.

General diet

Epalzeorhynchos frenatum var. is omnivorous, with a strong plant-based component in its diet. It grazes algae and biofilm from rocks, wood and aquarium glass, while readily accepting prepared foods. Offer sinking foods for bottom fish, quality pellets, algae-based foods and blanched vegetables such as zucchini or cucumber. Small portions of frozen foods can supplement the diet but should not become the main food source. A varied diet supports good coloration and limits competition at feeding time. Plant-based foods should be offered regularly.

Essential data

• Native river name: Mekong and associated river systems; the species is also linked to the Chao Phraya basin.
• Local name used: Rainbow shark; Albinos Rainbow Shark in the aquarium trade.
• Origin of the scientific name: The genus is a Greek or Latinized name referring to the snout; the specific epithet describes a feature associated with the mouth.
• Etymology of the full name: Epalzeorhynchos is formed from elements referring to a snout or rostrum; frenatum means “bridled” or “furnished with a bridle.” “var.” indicates a captive variety.
• Common/vernacular names: Albinos Rainbow Shark, Albino Rainbow Shark, albino rainbow shark.
• Family: Cyprinidae
• Subfamily: Labeoninae
• Name pronunciation: ep-al-zee-oh-RINK-os fren-AH-tum
• Discovery: Henry Weed Fowler, 1934.
• Maximum adult size: About 15 cm.
• Water temperature and pH: 23 to 28 °C; pH 6.5 to 8.0.
• Stream appearance and surrounding vegetation: Warm, clear to slightly stained waterways with moderate flow, roots, branches, submerged vegetation and planted banks.
• Typical tankmates: Crossocheilus oblongus, Botia kubotai, Devario aequipinnatus, Trigonostigma heteromorpha, Epalzeorhynchos bicolor.
• Temperament and behavior: Active, territorial and usually more aggressive toward its own kind; it uses shelters and patrols mainly near the bottom.
• Water depth: Shallow to moderately deep sections of streams and nearshore areas.
• Sexual dimorphism: Adult females are often stockier; males may be slimmer and more intensely colored.
• Bottom structure and flow: Sand, gravel, stones, wood and plant debris; low to moderate flow with good oxygenation.

In your aquarium

To succeed with Epalzeorhynchos frenatum var., provide an aquarium of at least 200 litres for one adult, with open swimming space and several shelters separated by plants, rocks or wood. Stable, warm and well-filtered water is essential. Avoid keeping several rainbow sharks in a small aquarium, since persistent chasing may develop. Feed a varied, plant-focused diet and monitor compatibility with peaceful bottom-dwelling fish. Its common availability should not obscure its territorial nature and need for adequate space.