A popular, active freshwater 'shark' (actually a cyprinid) known for its striking red fins contrasting with a dark or albino body. They are highly territorial bottom-dwellers. Only keep one per tank, as they are notoriously aggressive toward their own kind, other 'sharks' (like the Red Tail Shark), and similar-looking bottom feeders.
At a Glance
Tank Requirements
Water Parameters
Temperament & Compatibility
Available Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Standard
The standard wild-type form featuring a dark gray-to-black body with vibrant red or orange fins.
Same care requirements as the base species
Also known as: Black, Wild Type, Ruby
Albino
A widely available color morph sharing the exact same care requirements and territorial temperament, but featuring a pinkish-white body with bright red fins.
Same care requirements as the base species
Also known as: Albino Rainbow Shark, White, Pink
Rainbow Shark Care Guide Summary
The Rainbow Shark, scientifically known as Epalzeorhynchos frenatum, belongs to the Cyprinids family group. Adults reach a maximum size of approximately 15 cm and have a fusiform body shape with a moderate growth rate. Classified as aggressive, this species primarily occupies the bottom zone of the aquarium and produces a medium level of biological waste.
To thrive, the Rainbow Shark requires a freshwater only aquarium with a minimum volume of 200 litres and a tank length of at least 120 cm. Water temperature should be maintained between 22°C and 28°C, with a pH range of 6.5–7.5 and a general hardness of 5–15 dGH. A moderate water flow is preferred.
Due to its specialist needs, the Rainbow Shark is best suited for fishkeepers who can provide a carefully planned setup. This species is available in 2 varieties: Standard and Albino. Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.
Rainbow Shark Habitat Setup
When setting up an aquarium for the Rainbow Shark, a moderate water flow best suits their natural preferences. Because this species occupies the bottom zone, the aquarium layout should prioritise sufficient floor space with hiding spots among rocks, wood, or dense planting. Useful additions include a sand substrate to accommodate their sifting behaviour, smooth gravel or rounded substrate to protect their sensitive barbels, driftwood, which can serve as both a hiding place and a dietary supplement, and dense planting to provide cover, break sightlines, and reduce stress. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.
Rainbow Shark Compatibility Notes
Classified as aggressive, the Rainbow Shark is best housed alone, as they do not tolerate others of their kind in confined spaces. When choosing tankmates, conspecific aggression can be intense, especially in smaller tanks, territorial behaviour may cause issues if hiding spots or floor space are limited, and their energetic swimming style may stress more sedentary or timid species. Selecting tankmates that favour different water layers from the bottom zone can help reduce competition and territorial overlap.
Frequently Asked Questions About Rainbow Shark
How big does Rainbow Shark get?+
What tank size does Rainbow Shark need?+
What water parameters does Rainbow Shark need?+
Is Rainbow Shark peaceful or aggressive?+
Can Rainbow Shark live with others of its kind?+
Does Rainbow Shark have any special tank requirements?+
Does Rainbow Shark need a lid on the tank?+
Similar Species
Red Tailed Black Shark
Epalzeorhynchos bicolor
A striking and highly active bottom-dwelling cyprinid known for its jet-black body and vibrant red tail. While beautiful, they are notoriously territorial, especially toward their own kind, similar-looking species (like Rainbow Sharks), and sometimes other bottom-dwellers. They must be kept as the only 'shark' in the tank and require a large footprint with plenty of caves and broken sightlines.
Bala Shark
Balantiocheilos melanopterus
Despite its name, the Bala Shark is a peaceful, schooling cyprinid. They are extremely active, fast swimmers that grow very large and startle easily. They are notorious for injuring themselves by crashing into the aquarium glass if kept in small tanks or easily spooked. They must be kept in groups and eventually require massive, custom-sized aquariums.
Red Rainbowfish
Glossolepis incisus
Native to Lake Sentani in Indonesia, this species is famous for the brilliant salmon-red coloration of mature males. They are large, active schooling fish that develop a distinct high-arched back as they age. Females are vastly different in appearance (olive-gold). They require hard, alkaline water and plenty of swimming space.
Turquoise Rainbowfish
Melanotaenia lacustris
A stunning, deep-bodied rainbowfish endemic to Lake Kutubu in Papua New Guinea. Famous for their ability to shift colors from deep teal to bright iridescent blue depending on mood and water quality. They are active schooling fish that thrive in hard, alkaline water.
Threadfin Rainbowfish
Iriatherina werneri
A delicate and exquisitely shaped nano rainbowfish native to New Guinea and Northern Australia. They are famous for the males' long, filamentous fins and butterfly-like display behavior. Due to their incredibly small throats, they require micro-foods. They are shoaling fish that are easily intimidated by boisterous tank mates.
Tiger Barb
Puntigrus tetrazona
A highly active, schooling cyprinid famous for its striking black stripes and infamous reputation as a fin-nipper. They are boisterous and must be kept in larger groups (6+) to keep their pecking order internal. They should never be housed with slow-moving or long-finned tankmates like Bettas, Guppies, or Angelfish.