A queer fish

A queer fish: alguém estranho ou que age de maneira estranha

“Your great grandfather was a queer fish, Johnny. He used to write funny poems and then he'd read them aloud to everyone on the train on his way to work.”

“Some of the characters described as "queer fish" in old novels might be called "weirdos" these days.” (www.englishclub.com)