What Divers Should Know About Catfish

Venturing into freshwater and brackish environments, often in shallow, running waters, you’re likely to encounter the fascinating catfish. While most prefer these inland settings, some species, particularly from families like Ariidae and Plotosidae, have adapted to life in saltier coastal waters. These intriguing fish are found on every continent except Antarctica, showing incredible diversity, especially across tropical South America, Asia, and Africa. Known for being primarily bottom feeders, their characteristic negative buoyancy means they naturally hug the substrate, making them a common sight rooted to the lakebed or riverbed.

When you spot one, you’ll notice their distinctive appearance. Catfish famously lack scales, instead sporting either smooth skin – sometimes used for breathing – or, in many cases, impressive armor plates. Their namesake barbels, resembling a cat's whiskers, are usually prominent, helping them navigate and find food. With a flattened head ideal for digging, they typically feed by suction or gulping prey rather than biting. Some families even possess a specialized suckermouth, allowing them to cling effortlessly to objects even in swift currents. Keep an eye out during day or night dives, as while many are nocturnal, others are active during twilight or even broad daylight.