The river redhorse is a species of freshwater fish endemic to the eastern half of the United States and southeastern Canada. They can range from 10 to 30 inches in length and can potentially reach a weight of more than 10 pounds after maturity. It is typically found in clear, large creeks and rivers, though it is sometimes also found in lakes. They are sometimes speared or caught with hook and line using crayfish or worms as bait.
The Spanish toothcarp, also known as the Spanish pupfish or Iberian killifish, is a small, endemic species of fish in the family Cyprinodontidae. Its risk of extinction is one of the greatest of any Iberian vertebrate. Its limited range, coupled with the drastic population decline the species has suffered in the last two decades, has caused it to be placed on endangered species lists, both in Spain and internationally. In addition, habitat fragmentation, likely due to humans, has resulted in this species becoming increasingly stagnant and has led to increased genetic drift. Also found to be contributing to their endangerment was genetic diversity of mitochondrial DNA. The mitochondrial DNA coupled with A. iberus’s geographic distribution has been able to affect their population genetic structure gradually in different spaces. Its conservation status in the south of the Iberian peninsula has notably worsened.
The Cape whitefish or Berg-breede River whitefish is a ray-finned fish species in the family Cyprinidae. It is placed with the South African redfins in Pseudobarbus. It is tetraploid. Its closest living relative was at one time considered the sawfin.
The Iberian barbel is a ray-finned fish species in the family Cyprinidae. It is here placed in Luciobarbus following the IUCN, but that genus is very closely related to the other typical barbels and perhaps better considered a mere subgenus of Barbus. This large barbel can grow to over 50 cm (20 in) long.
Luciobarbus guiraonis is a ray-finned fish species in the family Cyprinidae. It is here placed in Luciobarbus following the IUCN, but that genus is very closely related to the other typical barbels and perhaps better considered a mere subgenus of Barbus.
Luciobarbus microcephalus is a ray-finned fish species in the family Cyprinidae. It is here placed in Luciobarbus following the IUCN, but that genus is very closely related to the other typical barbels and perhaps better considered a mere subgenus of Barbus.
The Northern straight-mouth nase is a species of ray-finned fish in the family Cyprinidae. It is found in Portugal and Spain. Its natural habitat is rivers. It is threatened by habitat loss.
The Iberian nase is a species of freshwater fish in the family Cyprinidae. It is found in Portugal and in Spain. Its natural habitats are rivers and intermittent rivers.
Pseudochondrostoma willkommii is a species of cyprinid fish. It is found in Portugal and Spain. Its natural habitats are rivers and water storage areas. It is threatened by habitat loss.
The Bayou darter is a rare species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to western Mississippi in the United States, where it is found only in Bayou Pierre and its tributaries. Its typical habitat is fast-flowing creeks and streams, in riffles and in areas between riffles with firm gravel bottoms. It feeds on small insects and their larvae. Breeding probably takes place twice a year, in spring and late summer. The population of this fish is declining due to loss of suitable habitat. This is caused by siltation and pollution, particularly erosion caused by changes in land use. The International Union for Conservation of Nature has assessed its conservation status as being "endangered".
The trispot darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to northern Georgia and southern Tennessee in the United States, where it occurs in the Conasauga River and its tributaries and historically in the Alabama River system. It requires two interconnecting habitats; outside the breeding season it occupies the peripheral zones of the main river, with slow-moving water and silt gravel substrates with vegetation cover; during the breeding season it moves to warmer water with a clay-bottomed substrate with much vegetation. The population of this fish is declining due to loss of suitable habitat because of stream impoundment and land development. The International Union for Conservation of Nature has assessed its conservation status as being "vulnerable".
Galaxias fontanus, the Swan galaxias, is a species of fish in the family Galaxiidae. It is endemic to eastern Tasmania, Australia.
The bluehead sucker is endemic to the intermountain Western US. A total of 23 members of the genus Catostomus has been found in North America. C. discobolus and C. yarrowi are two sister species that have very similar Arizona habitats.
The bigeye shiner is a species of ray-finned fish in the genus Notropis. This fish is a slender, silvery minnow with a dusky lateral stripe and a maximum total length of about 80 mm. Its distinct characteristic is its large-diameter eyes. It is a common species in upland streams of the middle Mississippi River system. Bigeye shiners prefer warm, quiet pools with clear water and silt-free substrates. Siltation, channelization, and gravel dredging are all threats to bigeye shiner populations. During spawning season, typically late April to August, bigeye shiners have several clutches of eggs. State agencies and the EPA have both played a role in the surveying of bigeye shiner populations. Populations have decreased in Ohio due mostly to habitat destruction. In addition to habitat destruction by humans, habitat alteration of the small streams and dried pools has also had a significant effect on abundance. Rivers and streams should not be channelized or modified in any way, which is becoming an increasingly popular trend in urban locations. Agricultural areas and properties within the watershed should adhere to regulations to prevent runoff into the streams.
Achondrostoma arcasii, termed the bermejuela, is a species of freshwater fish in the family Cyprinidae. It is found in the Douro River in northern Portugal and in rivers draining to both the Atlantic Ocean and the Mediterranean, including the Ebro River, in northern Spain where it is threatened by loss of habitat caused by the building of canals and the construction of dams, as well as by introduced predators and water pollution.
The bluebreast darter is a small species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to the eastern United States from New York and Illinois to Tennessee and North Carolina.
The relict darter is a rare species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to Kentucky, where it occurs only in the drainage of the Bayou de Chien. It is a federally listed endangered species of the United States.
The flame chub is a species of freshwater fish in the family Cyprinidae found only in the United States. Its range broadly follows the Tennessee River from above Knoxville, Tennessee, to the mouth of the Duck River. Historically the species was found in Kentucky, Tennessee, Alabama and Georgia. The preferred habitat of flame chub is in small flowing streams often associated with springs.
Squalius valentinus, commonly known as the Valencia chub and the Levantine bagra, is a species of freshwater fish in the carp family Cyprinidae. It was first isolated from the Turia River in Valencia, hence its name. It is considered endangered. This species is differentiated from its cogenerates by having eight branched rays in its dorsal fin; eight branched rays in its anal fin; two rows of pharyngeal teeth on both sides possessing 2 and 5 teeth ; a wide caudal peduncle; its number of gill rakers; the number of scales in its lateral line; the number of scale rows above the latter; by possessing three scale rows below it; by having thirty-nine vertebrae ; showing large 4th and 5th infraorbital bones; a maxilla with a very distinct marked anterior process; exhibiting a frontal bone expanded at the middle; a wide neurocranium bone; the lower branch of the pharyngeal bone being robust; a large and narrow urohyal; as well as genetic differences (allozymes).
Squalius malacitanus, commonly known as the Málaga chub, is a species of freshwater fish in the carp family Cyprinidae. It was first isolated from the Guadalmina River in Málaga, hence its name. It is considered a vulnerable species. S. malacitanus differs from its cogenerate species by having 7–8 branched rays in its dorsal fin, 8 branched rays in the anal lateral line; the number of scale rows above its lateral line; possessing 3 scale rows below its lateral line; 38 vertebrae, 21 abdominal, and 17 caudal; large fourth and fifth infraorbital bones; maxilla without a pointed anterior process; the middle of its frontal bone being narrow, as well as its neurocranium bone; the lower branch of its pharyngeal bone is rather long; and the shortness of the inferior lamina of its urohyal bone.
