Fish are an important resource for humans worldwide, especially as food. Commercial and subsistence fishers hunt fish in wild fisheries (see fishing) or farm them in ponds or in cages in the ocean (see aquaculture). They are also caught by recreational fishers, kept as pets, raised by fish keepers, and exhibited in public aquariam. Fish have had a role in culture through the ages, serving as deities, religious symbols, and as the subjects of art, books and movies.
Because the term "fish" is defined negatively, and excludes the tetrapods (i.e., the amphibians, reptiles, birds and mammals) which descend from within the same ancestry, it is paraphyletic, and is not considered a proper grouping in systematic biology.
i am a student of class 7. i love to write books especially related to science. i love science because it is informative.