What makes a fish a catfish? Well, first of all, it must have whiskers, or correctly, barbels. After all, that’s where the catfish got its name. These paired appendages remind some folks of the whiskers on our furry house pets. All North American catfish possess four pairs of barbels around the mouth. The barbels are organs of taste and feel. They’re sensitive to touch and covered with taste buds. Thus, they assist a catfish in finding food, even in muddy water. Some folks think the barbels can sting, but this is only a myth. Catfish also have sharp spines in their pectoral and dorsal fins. Unlike barbels, these can inflict painful wounds. Many “cats” have venom cells in the skin covering these spines. All catfish lack scales. There are those with smooth, naked skins (like our native cats), others with rows of spiny plates and even a few completely armored with overlapping shields. But no scales. They also possess a fleshy adipose fin on the rear of their back, like trout and salmon (below). More than 2,200 species of catfish swim the waters of the world (about 8 percent of the total number of fishes). They’re found on every continent except Antarctica and comprise what many fish scientists consider the most diverse group of fish on earth. There are bigger fish and littler fish, stranger fish, more beautiful fish and even uglier fish. But in no other group of fish does so much beauty and ugliness come together. On the ugly end of the scale is the wels, or sheatfish, the giant cat of Eurasian rivers and lakes. Individuals nearly 15 feet long and some weighing more than 600 pounds have been reported. Stories of children being swallowed whole by these fish are part of European folklore. They are said to devour birds and dogs swimming at the surface. The giant Mekong catfish, or pla buek, of Southeast Asia is another behemoth. It grows to 12 feet and 650 pounds. The goonah of India, a hulking catfish with a massive jaw, grows to 5 feet and weighs almost as much as a man. At least three South American cats – the redtailed cat, jau and azulejo – have been documented at weights over 200 pounds. They grow heavier, but big ones just can’t be caught. The vundu and sharptooth cats of Africa exceed 65 pounds. Among the more beautiful catfish are the many species of Corydoras and plecos popular with home aquarists. Many are brightly colored or covered with intricate designs of spots, speckles and stripes. The catfish family includes many unusual members as well. Africa’s electric catfish, an aggressive animal that may weigh more than 50 pounds, packs a punch of up to 300 volts, enough to run a hair dryer. The upside-down catfish is another African native. This little backswimmer starts out with the conventional dark back and light belly but takes to swimming upside down as it grows and ends up with a light-colored back and a dark-colored belly. The Asian glass catfish is transparent. If you look at one through a magnifying glass, you can see its heart beating. Should one die, it immediately turns milky white, a fact that suggests it does something while alive to maintain its transparency. The talking catfish of South America are also aptly named. These fish emit a high-pitched croaking noise, which can be surprisingly loud. The fish accomplishes this by grinding the base of its pectoral fin bone against its shoulder bone. Most, if not all, of the 80 to 100 species in this genus can “talk” in this manner. Amongst these are some true giants (4 feet plus), which must be eerie to hear. The most fearsome reputation belongs not to one of the giant catfish but to tiny South American cats called candirus. These 1/2-inch-long blood-sucking, eel-like cats have the unique distinction of being the only vertebrates that parasitize humans. They have the peculiar, and frightening, habit of entering the human genital opening, of either male or female, and worming their way up into the urethra where they erect prickly spines on their gill covers, embedding themselves within the body of their human host. Many victims die in agony. North America north of Mexico is home to 45 catfish species, quite a meager collection compared to other continents. But what we lack in quantity, we make up in quality. The “big three” of North American catfish – blue, flathead and channel – rank among the world’s largest.