A guest blog post by Tennessee Aquarium Conservation Institute Science Program Manager Dr. Bernie Kuhajda
What makes a catfish a catfish? First and foremost, all catfishes have whiskers. These are very different from the whiskers on a cat! Catfish whiskers have taste buds on them, which help catfish taste what is around them and helps them find food. This is especially important because catfishes do most of their feeding at night as they forage along the bottom, so whiskers (the scientific term is barbels) really help out at dinner time!
Catfishes in the U.S. have 8 whiskers, two behind each nostril, two at each corner of the mouth, and four on the chin.
Some folks try to avoid catfish whiskers because they are under the impression that they will sting you, but this is not the case.
What will sting or jab you is the second feature that makes a catfish a catfish, spines on the front of their fin on their back (dorsal fin) and fins on their sides (pectoral fins). Not only does a spine piercing you skin hurt, but some catfishes have venom cells in the skin covering their spines, and when they rupture they release the venom and it feels like a bee or wasp sting!
None of the catfishes in the U.S. can cause serious harm with their spine venom, but in other parts of the world some catfishes have venom sacs at the base of the spine that can inject enough venom to seriously harm, and even kill a person.
Number three on the list of catfish characteristics is no scales, with most catfishes having smooth skin. But some catfishes, like armored catfish in South America, have bony plates covering most or all of their body for protection.
The last thing that makes a catfish a catfish is the smaller second fin on their back close to their tail fin. This fin (adipose fin) is a fleshy tab that lacks the fin rays found in other fins. In some smaller catfishes, like our North American madtom catfishes, the adipose fin is longer and almost connects with the tail fin.
Catfishes are, or were, found on every continent in the world; there are fossil catfishes in Antarctica that date back to perhaps 40 million years ago!
Currently there are over 4,000 described species of catfishes in the world, grouped into 41 different families, with new species being described every year. Catfishes live in a variety of habitats, including some that live in oceans along the coast and some in caves where they are white and have lost their eyes.
So now you know what makes a catfish a catfish! Not only do they taste good, they are also very interesting fishes that are found in backyard streams and rivers and all over the w world!