Common name
Rainbow shark
Scientific name
Epalzeorhynchos frenatum
Category
Freshwater fish
Group
Labeonins and algae grazers
Environment
Freshwater
Origin
Mekong and Chao Phraya basins of mainland Southeast Asia, including Thailand, Laos, Cambodia and Vietnam
Care level
Intermediate
Adult size
About 12–15 cm total length
Expected lifespan
About 6–10 years
Minimum housing
At least 250 L with a long footprint and one large, structured bottom territory
Temperature
22–27 °C
pH
6.5–8.0
Hardness / minerals
Soft to moderately hard
Salinity
Freshwater
Lighting
Moderate, supporting some biofilm but retaining shaded refuge
Placement / swimming zone
Bottom and lower water

Identity and search names

Single-species profile for Epalzeorhynchos frenatum. Labeo frenatus is the original combination; similarly coloured Epalzeorhynchos are distinct species. Search names include Rainbow shark, Red-fin shark, Green fringelip labeo, Labeo frenatus, Epalzeorhynchos frenatum.

Environment and housing

Long covered aquarium with smooth substrate, wood, rocks, tunnels, sight breaks, current and high oxygen, while preserving open bottom routes

Feeding and nutrition

Feeding ecology: Omnivorous grazer; algae and biofilm, plant-rich sinking foods, vegetables and small invertebrate foods

Feeding routine: Feed once or twice daily at the bottom and maintain grazing surfaces; do not expect algae alone to sustain the fish

Breeding and reproduction

Commercial propagation generally relies on controlled hormone induction. A dependable natural home-aquarium breeding method is not established.

Parental care: No aquarium parental-care protocol

Detailed husbandry

Identity scope
Single-species profile for Epalzeorhynchos frenatum. Labeo frenatus is the original combination; similarly coloured Epalzeorhynchos are distinct species.
Adult size and space
About 12–15 cm total length. At least 250 L with a long footprint and one large, structured bottom territory. Plan around adult dimensions, activity, social structure, aggression and waste production rather than sale size.
Social structure
Usually keep one per aquarium; conspecifics require substantially larger, carefully divided space
Swimming zone
Primary zone: Bottom and lower water. Keep that zone usable for movement, feeding and refuge.
Feeding ecology
Omnivorous grazer; algae and biofilm, plant-rich sinking foods, vegetables and small invertebrate foods
Feeding plan
Feed once or twice daily at the bottom and maintain grazing surfaces; do not expect algae alone to sustain the fish
Water stability
Maintain 22–27 °C; pH 6.5–8.0; hardness/minerals: Soft to moderately hard. Stable oxygenation and nitrogen-cycle control matter more than chasing one exact number.
Habitat structure
Long covered aquarium with smooth substrate, wood, rocks, tunnels, sight breaks, current and high oxygen, while preserving open bottom routes
Compatibility plan
Avoid other rainbow sharks, red-tail sharks and similar elongated bottom grazers in ordinary housing; choose robust midwater fish that do not enter its territory
Breeding plan
Commercial propagation generally relies on controlled hormone induction. A dependable natural home-aquarium breeding method is not established. Parental care: No aquarium parental-care protocol.
Quarantine
Quarantine new fish in a separate cycled aquarium with dedicated equipment. Match temperature and mineral chemistry gradually, confirm feeding, respiration, skin, fins and waste, and never add transport water to the established aquarium.
Welfare checks
Maintain the stated adult space and social structure, verify feeding and intervene early when injury, exclusion, weight loss, abnormal respiration or altered behaviour appears. The juvenile community-fish label is misleading. Adult territoriality and a 15 cm body require a long 250 L-plus aquarium, not a small algae-control role.
Biosecurity and release
Never release fish, fry, eggs, aquarium water, sediment, plants or live foods into drains, dams or natural waterways. Confirm current Australian import conditions and South Australian possession, trade and movement rules before acquisition or transfer.
Main risk
The juvenile community-fish label is misleading. Adult territoriality and a 15 cm body require a long 250 L-plus aquarium, not a small algae-control role.

Welfare and risk

Main risk

The juvenile community-fish label is misleading. Adult territoriality and a 15 cm body require a long 250 L-plus aquarium, not a small algae-control role.

Maintain the stated adult space and social structure, verify feeding and intervene early when injury, exclusion, weight loss, abnormal respiration or altered behaviour appears. The juvenile community-fish label is misleading. Adult territoriality and a 15 cm body require a long 250 L-plus aquarium, not a small algae-control role.

Sources