FishChecker

The Columbian Shark, scientifically known as Arius seemani, is a captivating and often misunderstood species that brings a distinctive predatory presence to the right aquarium. Despite its common name, it is a member of the catfish family, characterized by its sleek, streamlined body, shimmering silver coloration, and prominent barbels that give it a striking resemblance to a miniature marine shark. Growing quite large, typically reaching 1 to 2 feet (30-60 cm) in captivity, this fish demands a remarkably spacious environment; a minimum of 100 gallons for juveniles, with mature adults requiring tanks of 200-300+ gallons to thrive and accommodate their active swimming behavior. A crucial consideration for their care is their water parameter requirements: while frequently sold as a freshwater fish, Columbian Sharks are obligate brackish water species as juveniles, gradually transitioning to full marine conditions as they mature. Maintaining a specific gravity of 1.005-1.015, slowly increasing over time, is vital for their long-term health; prolonged exposure to pure freshwater will lead to severe health issues and a significantly shortened lifespan. They are generally peaceful with appropriately sized tank mates but will readily consume any fish small enough to fit into their mouths. Compatible companions include other large, robust brackish water species such as Archerfish, Scats, and large mollies. Provide a substrate of sand or fine gravel, along with ample open swimming areas and some scattered rocks or driftwood for occasional hiding spots. Their diet should be varied, consisting of high-quality sinking pellets, flakes, and a mix of meaty foods like frozen bloodworms, brine shrimp, and chopped earthworms. Robust filtration is essential given their size and feeding habits. The Columbian Shark is a highly rewarding species for experienced aquarists prepared to meet its unique brackish water needs, offering a truly engaging and unique display.

Requires brackish water, transitioning to full marine. Will eat smaller fish.