What was they sold as then, I refuse to believe anyone can confuse them with another species. Unless you want to buy a 12 foot intex pond and pond filtration, heating and lose a room of your house to set it up.... All within a year lol. Take em back. We've all been caught out, I've had alligator gar that only get 16" and red snakehead that get 15" when I was a beginner, I since love purposefully asking about them in shops just so I can shoot down the spotty know nothing idiots about various species...
Most arnt even enthusiastic about fish but merely after shifting as much fish for as much dollar as possible no matter the cost.