Golden shiner

The golden shiner (Notemigonus crysoleucas) is a species of freshwater ray-finned fish belonging to the family Leuciscidae. This fish occurs in eastern North America. It is the sole member of its genus. Commonly used as a bait fish, it is probably the most widely pond-cultured fish in the United States. It can be found in Quebec and elsewhere in southeastern Canada west to Manitoba or Saskatchewan, and its French name is Méné jaune or Chatte de l'Est.

It is the only North American member of the subfamily Leuciscinae, within which it occupies a relatively basal position, though still rather derived. All other members of this subfamily are found in Eurasia. Fossil remains of Notemigonus sp. have been recovered from the Late Miocene–aged Montbrook fossil site of Florida, US.

Though it has been known to reach a total length (TL) of 36.7 cm (14.4 in), in the wild mature golden shiners are usually between 7 and 20 cm (2.8 and 7.9 in) TL. The body is laterally compressed (deep-bodied). The back is dark green or olive, and the belly is a silvery or brassy white. The sides are silver in smaller individuals, and in clear or turbid water, but golden in larger ones living in stained water. There can be a faint dusky stripe along the sides. The anal fin is large and has 8–19 rays, while the dorsal fin comprises seven to nine rays, typically eight. Scales are relatively large in the adult and easily lost when the fish is handled. The mouth is small and upturned. The eyes are yellow-green, as are the median and pelvic fins, though spawning males can develop orange coloration in these fins, especially in their distal leading rays.

Two characteristics can distinguish the golden shiner from all other North American minnows: (1) the lateral line has a pronounced downward curve, with its lowest point just above the pelvic fins; and (2) there is a fleshy keel lacking scales on the belly between the pelvic fins and the base of the anal fin.

The lack of scales on the keel is important to differentiate the golden shiner from the very similar-looking rudd, Scardinius erythrophtalmus, a European species that has been introduced in a few places in North America. The rudd also has a midventral keel, but that keel bears scales. Golden shiner and rudd can in fact hybridize, and hybrids have a few scales on their midventral keel.

The golden shiner is found throughout the eastern half of North America, north to the St Lawrence River, Great Lakes, and Lake Winnipeg, and west to the Dakotas and Texas. It is found as far south as southern Florida and Texas. Because of its use as bait, it has also been introduced in many places outside this native range, especially in western North America.

Golden shiners prefer quiet waters and are therefore found in lakes, ponds, sloughs, and ditches. They are sometimes found in the quietest parts of rivers, and like weedy areas. They are fairly tolerant of pollution, turbidity, and low oxygen content. They can also tolerate temperatures as high as 40 °C (104 °F), which is unusually high for a North American minnow.^{[page needed]}

Golden shiners are omnivorous and crepuscular planktivores. They eat zooplankton, phytoplankton, microcrustaceans, insects, plants, and algae. They can feed at the surface, in mid-water, or at the bottom. They can locate prey visually, or filter-feed on high-density zooplankton without resorting to visual cues. They are themselves food for all manner of game fish such as trout and bass (black bass and temperate bass,) hence their popularity as bait fish.