Where does sounds fishy come from?

The phrase "sounds fishy" likely originates from the idea that something that seems suspicious or untrustworthy can evoke the image of something fishy or rotten. The expression plays on the notion that fish, particularly if they are old or spoiled, can emit an unpleasant odor, suggesting that a situation or statement may not be genuine or honest. This idiom has been in colloquial use for many years, often used to express skepticism or doubt about someone's claims or actions.