Why is mudskipper a fish?

Mudskippers are not fish, they are amphibians. They are classified in the family Gobiidae, which is a family of fish, but mudskippers have adapted to live both in and out of water. They can breathe air through their gills and skin, and they can use their fins to walk on land. Mudskippers are found in mangrove swamps and other coastal areas where they feed on small invertebrates.