Cyprinodontiformes is an order of ray-finned fish, comprising mostly small, freshwater fish. Many popular aquarium fish, such as killifish and live-bearers, are included. They are closely related to the Atheriniformes and are occasionally included with them. A colloquial term for the order as a whole is toothcarps, though they are not actually close relatives of the true carps – the latter belong to the superorder Ostariophysi, while the toothcarps are Acanthopterygii.
Perciformes, also called the Percomorpha or Acanthopteri, is an order or superorder of ray-finned fish. If considered a single order, they are the most numerous order of vertebrates, containing about 41% of all bony fish. Perciformes means "perch-like". This group comprises over 10,000 species found in almost all aquatic ecosystems.
The Scorpaeniformes are a diverse order of ray-finned fish, including the lionfish, but have also been called the Scleroparei. It is one of the five largest orders of bony fishes by number of species, with over 1,320.
Characiformes is an order of ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, more than 2000 different species are described, including the well-known piranha and tetras.
Cypriniformes is an order of ray-finned fish, including the carps, minnows, loaches, and relatives. This order contains 11-12, although some authorities have designated as many as 23, families over 400 genera, and more than 4,250 species, with new species being described every few months or so, and new genera being recognized frequently. They are most diverse in southeastern Asia, and are entirely absent from Australia and South America. At 112 years old, the longest-lived cypriniform fish documented is the bigmouth buffalo.
Ophidiiformes is an order of ray-finned fish that includes the cusk-eels, pearlfishes, viviparous brotulas, and others. Members of this order have small heads and long slender bodies. They have either smooth scales or no scales, a long dorsal fin and an anal fin that typically runs into the caudal fin. They mostly come from the tropics and subtropics, and live in both freshwater and marine habitats, including abyssal depths. They have adopted a range of feeding methods and lifestyles, including parasitism. The majority are egg-laying, but some are viviparous.
The Osmeriformes are an order of ray-finned fish that includes the true or freshwater smelts and allies, such as the galaxiids and noodlefishes; they are also collectively called osmeriforms. They belong to the teleost superorder Protacanthopterygii, which also includes pike and salmon, among others. The order's name means "smelt-shaped", from Osmerus + the standard fish order suffix "-formes". It ultimately derives from Ancient Greek osmé + Latin forma, the former in reference to the characteristic aroma of the flesh of Osmerus.
Aulopiformes is a diverse order of marine ray-finned fish consisting of some 15 extant and several prehistoric families with about 45 genera and over 230 species. The common names grinners, lizardfishes and allies, or aulopiforms are sometimes used for this group. The scientific name means "Aulopus-shaped", from Aulopus + the standard fish order suffix "-formes". It ultimately derives from Ancient Greek aulós + Latin forma, the former in reference to the elongated shape of many aulopiforms.
The Beryciformes are a poorly-understood order of carnivorous ray-finned fishes consisting of 7 families, 30 genera, and 161 species. They feed on small fish and invertebrates. Beyond this, little is known about the biology of most member species because of their nocturnal habits and deepwater habitats. All beryciform species are marine and most live in tropical to temperate, deepwater environments. Most live on the continental shelf and continental slope, with some species being found as deep as 2,000 m (6,600 ft). Some species move closer to the surface at night, while others live entirely in shallow water and are nocturnal, hiding in rock crevices and caves during the day. Several species are mesopelagic and bathypelagic. Beryciformes' bodies are deep and mildly compressed, typically with large eyes that help them see in darker waters. Colors range from red to yellow and brown to black, and sizes range from 8–61 cm (3.1–24.0 in). Member genera include the alfonsinos, squirrelfishes, flashlight fishes, fangtooth fishes, spinyfins, pineconefishes, redfishes, roughies, and slimeheads. A number of member species are caught commercially, including the alfonsino, the splendid alfonsino, and the orange roughy, the latter being much more economically important. Some species have bioluminescent bacteria contained in pockets of skin or in light organs near the eyes, including the anomalopids and monocentrids.
The Atheriniformes, also known as the silversides, are an order of ray-finned fishes that includes the Old World silversides and several less-familiar families, including the unusual Phallostethidae. The order includes at least 354 species. They are found worldwide in tropical and temperate marine and freshwater environments.
Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration. Females brood their young in a pouch under their thorax.
The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the basis of the adult mouthparts. Integripalpian larvae construct a portable casing to protect themselves as they move around looking for food, while Annulipalpian larvae make themselves a fixed retreat in which they remain, waiting for food to come to them. The affinities of the small third suborder Spicipalpia are unclear, and molecular analysis suggests it may not be monophyletic. Also called sedge-flies or rail-flies, the adults are small moth-like insects with two pairs of hairy membranous wings. They are closely related to the Lepidoptera which have scales on their wings; the two orders together form the superorder Amphiesmenoptera.
The superorder Elopomorpha contains a variety of types of fishes that range from typical silvery-colored species, such as the tarpons and ladyfishes of the Elopiformes and the bonefishes of the Albuliformes, to the long and slender, smooth-bodied eels of the Anguilliformes. The one characteristic uniting this group of fishes is they all have leptocephalus larvae, which are unique to the Elopomorpha. No other fishes have this type of larvae.
The Syngnathiformes are an order of ray-finned fishes that includes the pipefishes and seahorses.
Alcyonacea, or soft corals, are an order of corals. In addition to the fleshy soft corals, the order Alcyonacea now contains all species previously known as "gorgonian corals", that produce a more or less hard skeleton, though quite different from "true" corals (Scleractinia). These can be found in suborders Holaxonia, Scleraxonia, and Stolonifera. They are sessile colonial cnidarians that are found throughout the oceans of the world, especially in the deep sea, polar waters, tropics and subtropics. Common names for subsets of this order are sea fans and sea whips; others are similar to the sea pens of related order Pennatulacea. Individual tiny polyps form colonies that are normally erect, flattened, branching, and reminiscent of a fan. Others may be whiplike, bushy, or even encrusting. A colony can be several feet high and across, but only a few inches thick. They may be brightly coloured, often purple, red, or yellow. Photosynthetic gorgonians can be successfully kept in captive aquaria.
An eel is a ray-finned fish belonging to the order Anguilliformes, which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage, and most are predators.
The anglerfish are fish of the teleost order Lophiiformes. They are bony fish named for its characteristic mode of predation, in which a modified luminescent fin ray acts as a lure for other fish. The luminescence comes from symbiotic bacteria, which are thought to be acquired from seawater, that dwell in and around the esca.
Scombriformes is an order of bony fish containing nine families which were classified under the suborders Scombroidei and Stromateoidei, of the wider grouping known as Perciformes, Nelson (2016) recognised the order but subsequent workers have suggested that Scombriformes forms part of the larger Pelagiaria clade.
Goby is a common name for many species of small to medium sized ray-finned fish, normally with large heads and tapered bodies, which are found in marine, brackish and freshwater environments. Traditionally most of the species called gobies have been classified in the order Perciformes as the suborder Gobioidei but in the 5th Edition of Fishes of the World this suborder is elevated to an order Gobiiformes within the clade Percomorpha. Not all the species in the Gobiiformes are referred to as gobies and the "true gobies" are placed in the family Gobiidae, while other species referred to as gobies have been placed in the Oxudercidae. Goby is also used to describe some species which are not classified within the order Gobiiformes, such as the engineer goby or convict blenny Pholidichthys leucotaenia. The word goby derives from the Latin gobius meaning "gudgeon", and some species of goby, especially the sleeper gobies in the family Eleotridae and some of the dartfishes are called "gudgeons", especially in Australia.
Ovalentaria is a clade of ray-finned fishes within the Percomorpha, referred to as a subseries. It is made up of a group of fish families which are referred to in Fishes of the World's fifth edition as incertae sedis, as well as the orders Mugiliformes, Cichliformes, and Blenniiformes. It was named by W. L. Smith and T. J. Near in Wainwright et al. (2012) based on a molecular phylogeny, but the authors suggested that the group was united by the presence of demersal eggs that are attached to a substrate. Some authors have used the ordinal name Stiassnyiformes for a clade including Mugiloidei, Plesiopidae, Blenniiformes, Atherinomorpha, and Cichlidae, and this grouping does appear to be monophyletic.
