Aquaculture is the production of marine and freshwater organisms under controlled conditions. Hundreds of different species of aquatic animals are raised in aquaculture and include fish and aquatic invertebrates cultured for food, the aquarium hobby, bait, recreational fisheries, research, private ponds, and stock enhancement of wild populations. Animal aquaculture was valued at $231.6 billion (USD) worldwide in 2016. China is currently the largest producer, accounting for approximately 61.5% of the world total tonnage of food fish. By contrast, North America (including the US) accounts for approximately 0.8%. Within the US, major commercial commodities include channel catfish, centered around the Mississippi Delta; rainbow trout in the north/northwest, including Hagerman Valley, Idaho; Atlantic salmon in the Pacific northwest and Atlantic northeast; aquarium fish Overview of Aquarium Fishes Aquatic medicine has emerged as a recognized specialty within the practice of zoologic medicine. Fish medicine, an important component of the aquatic specialty, is evolving, with distinct subspecialties... read more with production centered in Florida; baitfish in Arkansas; and goldfish and koi production scattered throughout the US. In addition, other public and private entities, including research facilities, public aquaria, and hobbyists, are breeding numerous other species.