It's a uro, and a male, spot at base of tail, in fesate the spot is small and at the top of the tail, uropthalmus the spot is large and centers at the base of the tail. The Florida fish farmers all sell Uros as Red terrors, one of the biggest scams in the hobby right now. I like uros, but hate when fish are sold under the wrong name, that's why you should never use common names, learn the latin. Ken