The primary difference between fish and amphibians is that fish are only able to live in water and amphibians are able to live both in and out of water. Other differences between fish and amphibians include habitat, differences in skin type and the presence of limbs.
As a class of animals, fish are much older than amphibians, which evolved 370 million years ago during the Devonian period. Amphibians were the first category of vertebrates, or animals with spines, that evolved from fish and left their aquatic habitats to colonize dry land.
While fish propel themselves through water with fins or float along underwater currents and do not have limbs, amphibians do have limbs and can run, jump, climb or swim both on land and in water. Whereas fish breathe by filtering oxygen from water through their gills, amphibians do not possess gills and are able to breathe air, although some are able to hold their breath underwater for extended periods of time. Fish are covered in scales and their skin does not allow material to pass through; amphibians have permeable skin, which allows gas and molecules to pass through. Some common amphibians include frogs, toads salamanders and newts. Some common fish include catfish, sharks, salmon, trout and sturgeon.