The main difference between Chilean sea bass and sea bass lies in their species. Chilean sea bass, also known as Patagonian toothfish, is a species found in cold, deep waters around Antarctica and South America. Sea bass, on the other hand, refers to various species of fish found in different parts of the world, such as European sea bass (found in Europe) or black sea bass (found in North America). While they may share similar names, they are different species with distinct characteristics and flavors.