Rainbow Shark (Epalzeorhynchos frenatum)

Rainbow Shark (Epalzeorhynchos frenatum)

The Rainbow Shark is a popular and eye-catching aquarium fish, well-loved for its bold colors and lively nature. Despite its name, it’s not actually a shark but belongs to the cyprinid family, making it a close relative of minnows. This energetic fish spends much of its time exploring the tank, grazing on algae and other microorganisms. While young Rainbow Sharks tend to be social, they become more territorial as they mature, especially toward similar-looking fish like Siamese Algae Eaters, Flying Foxes, and Garra species.

Care & Tank Setup

Rainbow Sharks are hardy and adapt well to a variety of water conditions. They thrive in tanks with strong filtration and moderate to high water flow. Since they are known to jump, having a secure lid on the aquarium is highly recommended.

This species is generally peaceful but can be territorial, especially with its own kind. To reduce aggression, they should either be kept alone or in groups of at least six in a spacious tank with plenty of hiding spots. Providing ample space and structured territories helps minimize conflicts.

Diet & Feeding

Rainbow Sharks are omnivores and will eat a variety of foods. They readily accept high-quality dry foods but also benefit from fresh vegetables like zucchini and cucumber. A balanced diet should also include live, frozen, and dry meaty foods to ensure they stay healthy and maintain their vibrant colors.

Why Choose a Rainbow Shark?

• Stunning, vibrant coloration
• Hardy and adaptable to a range of conditions
• Active and engaging behavior
• Does not eat live plants
• Generally peaceful with most fish and larger invertebrates

Tank & Water Requirements:

• Temperature: 68° - 79°F (20° - 26°C)
• pH Range: 6.5 - 8.0 (mid-range is ideal)
• KH: 2 - 15 dKH
• Minimum Tank Size: 55 gallons for a single adult

Care Guidelines:

• Diet: Omnivorous – thrives on a mix of high-quality dry foods, frozen foods, and fresh vegetables
• Social Behavior: Peaceful as a juvenile, but can become territorial with age; best kept alone or in a properly sized group
• Origin: Tank-bred, native to Thailand, Cambodia, and Laos
• Adult Size: 5 - 6 inches (13 - 15 cm)
• Juvenile Size at Purchase: Typically 1 - 2 inches (2.5 - 5 cm)

Rainbow Sharks add both color and personality to a freshwater aquarium. With the right care and setup, they make a fantastic addition to a well-maintained tank!