Catfish are well named - they have what appear to be whiskers around their mouths.
Those whiskers have made catfish almost mythical. Thanks to folklore passed down from generation to generation, some people believe that the whiskers contain venom and can sting anyone who touches one.
The real name for the appendages is barbels, said Spring Reilly, central region outreach and education coordinator with the state Fish and Boat Commission.
Every species of catfish bears eight barbels - four on the upper jaw and four on the chin.
"The barbels are fleshy, supple projections that narrow to a tip," Reilly said. "The barbels do not inflict the notorious sting of the catfish. That's a common misconception."
Barbels do play a important role to the fish's survival.
"The sensitive barbels are loaded with tiny tastebuds and olfactory (sense of smell) sensors that help the fish search for food," Reilly said. "Although catfish have tastebuds elsewhere on their bodies, most of them are located on the barbels."
In murky water, the appendages provide a way for catfish to "taste their way" to their food.
But catfish can injure an unwary angler. The parts that actually can harm a person are the pectoral fin spines on each side of the fish and the dorsal fin.
"The species have variously developed poison glands at the base of these spines, which can inflict a mild to bee-like sting," Reilly said. "There is a disagreement among scientists whether it's the gland at the base of the spine or the membrane around the spine that has the poison."
Catfish also have a stout spine on the edge of the dorsal fin.
Of the 40 species of freshwater catfish, Pennsylvania has 13. Three of them commonly are called bullheads and three are called catfish.
Yellow and brown bullheads are found throughout the state and black bullheads can be found in western Pennsylvania and in the Ohio River watershed.
Channel, flathead and white catfish are avidly sought by anglers, Reilly said.
Catfish can be found in all sizes all across the world. One of the largest catfish ever caught was a Mekong giant that measured about 9 feet long.
The flathead catfish found in Pennsylvania can grow large, too. A record of more than 40 pounds once was recorded in the state.
Much smaller catfish species are called madtoms. They are a reclusive species, not likely to be seen by anglers unless they really are looking for them.
Because of their miniature size and secretive nature, they sometimes are rare and scattered in distribution, she said.
"Two madtoms are endangered species in Pennsylvania and are found only in French Creek, in the northwest corner of the state," Reilly said.
The mountain madtom and northern madtom are endangered. Neither grows more than 4 inches in length.
The brindle madtom is a threatened species.
Some of the madtoms are especially known for their stinging spines.
"At the other end of the catfish family scale are the blue catfish and flathead catfish, which can grow more than 100 pounds and 4 or 5 feet long," Reilly said.
Smaller catfish are a big part of the forage base for other small fish in their home lakes and streams, she said. Some madtoms are considered water quality indicators.
After spawning in the spring and early summer, male and female catfish contribute to the construction of a nest, which usually can be found in holes in the river or lake banks, in the open, under rocks and other submerged objects.
Both parents guard the nest and even protect the young for a time.
They are active not only at night but during the daytime hours. In the day, they usually are found in murky, muddy or cloudy water.
Catfish, unlike most other fish species, do not have scales. They have tough, smooth skin.
Catfish are one of the most popular sporting fish and frequently are raised commercially for human consumption.
Some of the best live bait used to catch catfish are crawfish, chubs, minnows, shrimp and cut bait.