If you describe a situation as fishy, you feel that someone is not telling the truth or behaving completely honestly. There seems to be something fishy going on. = suspicious
not as expected; "there was something fishy about the accident"; "up to some funny business"; "some definitely queer goings-on"; "a shady deal"; "her motives were suspect"; "suspicious behavior"
Extravagant, like some stories about catching fish; improbable; also, rank or foul