Monkeys are animals that are known to swing from tree to tree. They are hairy and usually yell loudly. They are a mammal and under the class of Mammalia. Their order is primates. Many mammals and other types of animals share common traits. However, that doesn’t mean that the animal is now a mammal because they have the same characteristics.
Instead, they each are considered either a mammal, reptile, amphibian, etc. This is only because of the characteristics that identify each animal to fall in a specific category. Monkeys may be able to hold their breath for an extended period underwater, but they do not have gills like the fish do. Therefore, they can’t be considered fish.