Contrary to popular belief, fresh fish shouldn’t smell intensely fishy. In fact, truly fresh seafood has a clean, mild aroma that reminds many people of the sea. As the fish ages, bacteria naturally begin breaking down proteins, producing the strong odour many people associate with seafood. If the smell is overpowering, sour or unpleasant enough to make you step back, it’s usually best to leave that fish behind. When buying seafood, your nose can often detect problems before your eyes can.