Fishkeeping is a popular hobby, practiced by aquarists, concerned with keeping fish in a home aquarium or garden pond. There is also a piscicultural fishkeeping industry, serving as a branch of agriculture.Fish have been raised as food in pools and ponds for thousands of years. Brightly colored or tame specimens of fish in these pools have sometimes been valued as pets rather than food. Many cultures, ancient and modern, have kept fish for both functional and decorative purposes.Fishkeepers are often known as "aquarists" since many of them are not solely interested in keeping fish. The hobby can be broadly divided into three specific disciplines, depending on the type of water the fish originate from: freshwater, brackish, and marine (also called saltwater) fishkeeping.