The Iridescent Shark (Pangasianodon hypophthalmus) is a large, fast-swimming freshwater fish known for its shimmering, metallic body and shark-like appearance. Despite its name, it is not a true shark but rather a species of freshwater catfish native to the Mekong and Chao Phraya River basins in Southeast Asia. This species requires an exceptionally large tank and is best suited for experienced fish keepers with ample space.
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A Name That Reflects Its Appearance
The “Iridescent” name comes from the metallic sheen of its body, which reflects light beautifully, giving off shades of silver, blue, and purple. As juveniles, they are particularly vibrant, but their color can darken slightly as they grow.
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Growth and Tank Requirements
Iridescent Sharks grow to an impressive size of 3-4 feet in captivity and even larger in the wild. Due to their fast growth and highly active nature, they require an enormous aquarium of at least 300 gallons, with larger tanks (500+ gallons) being ideal. They need plenty of open swimming space, a strong filtration system, and a secure lid, as they are known to jump when startled.
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Care and Water Parameters
These fish thrive in warm, well-oxygenated water, with:
Temperature: 72-80°F
pH Range: 6.5-7.5
Water Hardness: Soft to moderately hard
Iridescent Sharks produce a high bioload, meaning a powerful filtration system and regular water changes are essential for maintaining water quality. They also prefer dim lighting and moderate water flow, mimicking their natural river environment.
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Diet and Feeding
Iridescent Sharks are omnivorous, requiring a balanced mix of plant-based and protein-rich foods. Their diet should include:
High-quality sinking pellets and wafers
Fresh or frozen foods like shrimp, bloodworms, and small fish
Vegetables such as zucchini, peas, and spinach
Occasional fruit treats, such as melon or banana
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Unique Behaviors
These fish are highly active and skittish, often darting around the tank when startled. They are peaceful but can become nervous in small tanks or with overly aggressive tank mates. Since they are social fish, they do best in small groups of 3 or more, but only in tanks large enough to accommodate their size.
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Important Considerations
Iridescent Sharks are often misunderstood and improperly housed, as they are commonly sold as small juveniles without adequate information about their enormous adult size. They are not suitable for small home aquariums, and proper planning is essential before acquiring one.
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Please note that these are general guidelines, and for more accurate values, we encourage you to contact Living Aquarium by phone or in person. Within store hours, our team of experts are always happy to answer any questions you may have and provide personalized guidance on care.