any of numerous mostly freshwater bottom-living fishes of Eurasia and North America with barbels like whiskers around the mouth
"The angler spotted a large catfish lurking at the bottom of the murky river, its whisker-like barbels swaying in the current."
any fish of the order Siluriformes, mainly found in fresh water, lacking scales, and having barbels like whiskers around the mouth
"When I tried to chat with that new friend online, it turned out she was just a catfish pretending to be someone else entirely."
Someone who creates a fake profile on a social media platform in order to deceive people.
To fish for catfish
"The investigator realized she had been catfished when her date never showed up for their planned meeting at the coffee shop."
To create and operate a fake online profile to deceive (someone).