RAINBOW SHARK (Epalzeorhynchos frenatum)

Rainbow Shark

Scientific Name: Epalzeorhynchos frenatum

Description

The Rainbow Shark is a striking freshwater fish known for its deep black body contrasted by vivid red to orange fins. Despite its name, it is not a true shark but earns the nickname due to its torpedo-shaped body and upright dorsal fin. Active and eye-catching, Rainbow Sharks make a bold centerpiece fish in medium to large aquariums.

While visually appealing, this species is best suited for experienced hobbyists due to its territorial nature, especially as it matures.

Care Guide

Tank Size

• Minimum: 55 gallons

• Larger tanks are strongly recommended to reduce aggression and establish territories.

Water Parameters

• Temperature: 22–27°C (72–80°F)

• pH: 6.5–7.5

• Hardness: Soft to moderately hard

• Clean, well-oxygenated water with moderate flow is ideal.

Tank Setup

• Provide plenty of hiding spots using driftwood, rocks, caves, and dense plants.

• Break up lines of sight to help reduce territorial behavior.

• Use a secure lid—Rainbow Sharks are strong, fast swimmers.

Temperament & Compatibility

• Semi-aggressive and territorial, especially toward similar-shaped or bottom-dwelling fish.

• Do not keep with: Other Rainbow Sharks, Red Tail Sharks, or similar species.

• Good tank mates: Fast, mid-to-upper level swimmers such as barbs, larger tetras, danios, and rainbowfish.

• Best kept as a single specimen per tank.

Diet

• Omnivorous

• Feed a varied diet including:

  • High-quality sinking pellets or wafers

  • Algae wafers

  • Frozen foods (bloodworms, brine shrimp)

  • Blanched vegetables (zucchini, spinach)

• Regular vegetable matter helps maintain coloration and health.

Adult Size

• Up to 6 inches (15 cm)

Lifespan

• 5–8 years with proper care

Notes for Success

• Juveniles may appear peaceful, but aggression increases with age.

• Adequate space and thoughtful tankmate selection are key to long-term success.

• Not recommended for small or community nano tanks.