FishA fish (: fish or fishes) is an aquatic, craniate, gill-bearing animal that lacks limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period.
Cleaner fishCleaner fish are fish that show a specialist feeding strategy by providing a service to other species, referred to as clients, by removing dead skin, ectoparasites, and infected tissue from the surface or gill chambers. This example of cleaning symbiosis represents mutualism and cooperation behaviour, an ecological interaction that benefits both parties involved. However, the cleaner fish may consume mucus or tissue, thus creating a form of parasitism called cheating.
CichlidCichlids ˈsɪklᵻdz are fish from the family Cichlidae in the order Cichliformes. Cichlids were traditionally classed in a suborder, the Labroidei, along with the wrasses (Labridae), in the order Perciformes, but molecular studies have contradicted this grouping. On the basis of fossil evidence, it first appeared in Tanzania during the Eocene epoch, about 46–45 million years ago. The closest living relative of cichlids is probably the convict blenny, and both families are classified in the 5th edition of Fishes of the World as the two families in the Cichliformes, part of the subseries Ovalentaria.
Sea louseSea lice (singular: sea louse) are copepods (small crustaceans) of the family Caligidae within the order Siphonostomatoida. They are marine ectoparasites (external parasites) that feed on the mucus, epidermal tissue, and blood of host fish. The roughly 559 species in 37 genera include around 162 Lepeophtheirus and 268 Caligus species. The genera Lepeophtheirus and Caligus parasitize marine fish, in particular those species that have been recorded on farmed salmon.
Wild fisheriesA wild fishery is a natural body of water with a sizeable free-ranging fish or other aquatic animal (crustaceans and molluscs) population that can be harvested for its commercial value. Wild fisheries can be marine (saltwater) or lacustrine/riverine (freshwater), and rely heavily on the carrying capacity of the local aquatic ecosystem. Wild fisheries are sometimes called capture fisheries. The aquatic life they support is not artificially controlled in any meaningful way and needs to be "captured" or fished.
HermaphroditeA hermaphrodite (hərˈmæfrəˌdaɪt) is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are of different sexes, either male or female but not both, are gonochoric, which is the opposite of hermaphroditic. The individuals of many taxonomic groups of animals, primarily invertebrates, are hermaphrodites, capable of producing viable gametes of both sexes. In the great majority of tunicates, mollusks, and earthworms, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which either partner can act as the female or male.
Cleaning symbiosisCleaning symbiosis is a mutually beneficial association between individuals of two species, where one (the cleaner) removes and eats parasites and other materials from the surface of the other (the client). Cleaning symbiosis is well-known among marine fish, where some small species of cleaner fish, notably wrasses but also species in other genera, are specialised to feed almost exclusively by cleaning larger fish and other marine animals. Other cleaning symbioses exist between birds and mammals, and in other groups.
Animal colorationAnimal colouration is the general appearance of an animal resulting from the reflection or emission of light from its surfaces. Some animals are brightly coloured, while others are hard to see. In some species, such as the peafowl, the male has strong patterns, conspicuous colours and is iridescent, while the female is far less visible. There are several separate reasons why animals have evolved colours. Camouflage enables an animal to remain hidden from view.
AquariumAn aquarium (: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquatic reptiles, such as turtles, and aquatic plants. The term aquarium, coined by English naturalist Philip Henry Gosse, combines the Latin root aqua, meaning 'water', with the suffix -arium, meaning 'a place for relating to'.
Fish scaleA fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as well as possible hydrodynamic advantages. The term scale derives from the Old French escale, meaning a shell pod or husk. Scales vary enormously in size, shape, structure, and extent, ranging from strong and rigid armour plates in fishes such as shrimpfishes and boxfishes, to microscopic or absent in fishes such as eels and anglerfishes.