Introduction to pet fish medicine and surgery (Proceedings)
What are fish?
The group of animals commonly referred to as "fish" is a paraphyletic group of some 30,000-plus described species ( http://www.fishbase.org/). That is, it includes all of the descendants of the common ancestor of the vertebrates (subphylum Vertebrata) with the exception of the tetrapods (subclass Tetrapoda–amphibians, reptiles, birds, mammals, totaling around 23,000 species), a fairly significant branch of the subclass Sarcopterygii alongside lungfish and coelacanths. Included are the hagfish (order Myxiniformes), lampreys (order Petromyzontiformes), sharks, rays and chimaeras (class Chondrichthyes; sharks and rays comprise the subclass Elasmobranchii), the sturgeon and paddlefish (order Acipenseriformes), bowfin (order Amiiformes), gars (order Semionotiformes), and the hugely diverse teleost fish (division Teleostei), which comprise about 96% of extant fishes. For the sake of simplicity, the cartilaginous fish are often referred to simply as elasmobranchs, although this group excludes about 30 species of chimaeras, and the bony fish as teleosts, although the teleosts do not include other ray-finned fish such as gar, bowfin, paddlefish or sturgeon. Care must be taken when speaking inclusively of the whole or parts of the "fish" assemblage.
Tropical fish kept in aquaria include both freshwater and marine species. The vast majority of over 1000 species of fish kept by hobbyists are small freshwater. Marine tanks are more involved to keep and maintain, so numerically tropical marine fish comprise a much smaller portion of the pet fish population, but species diversity is comparable. Greater than 95% of freshwater fish in the pet trade are produced in aquaculture facilities, while the opposite is true for marine fish. Singapore is the world's largest exporter of tropical fish, while in the United States, Florida is the leading tropical fish aquaculture producing area, with much of the industry within an hour's drive of Tampa/St. Petersburg.Common groups of freshwater fishes kept by hobbyists:
• Cyprinidae, the minnows, over 2000 species. Barbs, rasboras, danios, (also carp, koi and goldfish).
Some representative marine fish families:
• Grammidae, basslets.