Rainbow Shark

The Rainbow Shark (Epalzeorhynchos erythrurus) is a striking and active freshwater fish known for its sleek black body and vibrant red fins. Despite its common name, this fish is not a true shark but gets its name from its shark-like appearance and active swimming behavior. These territorial fish make fascinating additions to larger aquariums where they can establish their territory and display their beautiful coloration. While they can be aggressive toward their own kind, they are generally peaceful with other tankmates when provided with adequate space.

Care Sheet – Rainbow Shark (Epalzeorhynchos erythrurus)

Temperament

• Semi-aggressive and territorial

• Best kept as one per tank unless in very large aquariums

Adult Size

• 6 inches

Minimum Tank Size

• 55 gallons for a single adult

Water Parameters

• Temperature: 72–79°F

• pH: 6.5–7.5

• Hardness: Soft to moderately hard (5–15 dGH)

• Ammonia/Nitrite: 0 ppm

• Nitrate: <20–30 ppm

Diet

• Omnivorous

• Feed a varied diet:

  • High-quality sinking pellets or wafers

  • Algae wafers and vegetable matter

  • Frozen or live foods: bloodworms, brine shrimp

• Feed once daily

Behavior & Compatibility

• Best with medium to large peaceful fish

• Compatible with:

  • Barbs, rainbowfish, larger tetras

  • Peaceful cichlids

  • Top and mid-water dwelling fish

• Avoid other bottom-dwelling fish and conspecifics

Aquarium Setup

• Provide plenty of hiding spots and territories

• Rocks, driftwood, and caves for shelter

• Efficient filtration for clean, well-oxygenated water

• Open swimming areas

Care Level

• Easy to moderate

• Good for intermediate aquarists

Lifespan

• 5–8 years with proper care

Special Notes

• Stunning black body with vibrant red fins

• Very territorial, especially toward similar-looking fish

• Active swimmer that patrols the bottom levels

• Not a true shark – member of the carp family