When buying, choose active fish with clean skin and no visible damage, ulcers, or white spots. Check the barbels: they should be intact, without erosion, which shows the fish was kept properly in the shop. Avoid specimens with a sunken belly or unnatural bloating. Note that sharp spines on the pectoral and dorsal fins tangle easily in nets, so handle the fish with care to avoid injury and damage to the net. In shops, catfish often hide, so ask the seller to show them feeding to check appetite and confirm they are not overly shy.