The sheepshead minnow or sheepshead pupfish (''Cyprinodon variegatus'') is a species of

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or h ...

in the family Cyprinodontidae, the

pupfish Pupfish are a group of small killifish belonging to ten genera of the family Cyprinodontidae of ray-finned fish. Pupfish are especially noted for being found in extreme and isolated situations. They are primarily found in North America, South ...

es. It is found in

salt marsh A salt marsh or saltmarsh, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. It is domin ...

and

estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...

environments and is native to the eastern coasts of North and Central America.

Description

The sheepshead minnow is a deep-bodied fish growing to a length of up to though a more normal length is . It is nearly half as deep as it is long, excluding its tail. It is laterally compressed with flat sides, an arched back and a small head with a flattened top. The small mouth is at the end of the snout and the teeth are large and wedge-shaped with three cusps. The pectoral fins are large and extend past the origins of the small pelvic fins. The origin of the anal fin hardly overlaps the trailing edge of the dorsal fin. The caudal peduncle is thick and the caudal fin is truncated and square-ended. The arrangement of the fins, the deep body and the tri-cuspid teeth help to distinguish this fish from the mummichog (''Fundulus heteroclitus''), which is found in the same habitats. The body is covered by large, circular scales, the ones on the cheeks and the top of the head and a single scale just above the pectoral fin being the largest. The male is generally larger and more deep-bodied than the female, with larger dorsal, pelvic and anal fins. The color of the sheepshead minnow is olive green above and yellowish below. Juveniles have irregular transverse dark bars and the females keep these as they mature, while the males lose theirs. The dorsal fin is dark while the pectoral, pelvic and anal fins are orange. During the breeding season the male becomes very colorful with steel blue upper parts in front of the dorsal fin, lustrous green upper parts behind and deep salmon-pink underparts.

Distribution and habitat

The sheepshead minnow is native to the eastern coast of the United States. Its range extends from

Cape Cod Cape Cod is a peninsula extending into the Atlantic Ocean from the southeastern corner of mainland Massachusetts, in the northeastern United States. Its historic, maritime character and ample beaches attract heavy tourism during the summer mon ...

southwards to the Yucatan peninsula in Mexico, also the West Indies. It is found in brackish water in bays, inlets, lagoons, saltmarshes and similar locations with little wave action and sandy or muddy bottoms. It is tolerant of wide variations in

salinity Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...

and is also found in hypersaline conditions.

Behavior

The sheepshead minnow is an

omnivore An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...

, eating both animal and vegetable matter. Its diet mainly consists of detritus, microalgae, crustacean larvae and other small invertebrates. Males are aggressive and will attack fish larger than itself, slashing its prey with its sharp teeth and devouring it when it is subdued. Breeding takes place in shallow water between April and September, the males competing fiercely for the females. A few eggs are spawned at a time, and these are fertilised by the males which grasp the females with their fins. The eggs clump together and sink to the seabed, connected by sticky threads. They hatch after five or six days. During the winter, this fish burrows into the soft

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (locomotion), the surface over which an organism lo ...

and remains

dormant Dormant, "sleeping", may refer to: Science *Dormancy Dormancy is a period in an organism's life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps ...

Uses

The sheepshead minnow is commonly kept as an aquarium fish. It is easy to breed in captivity and is used as a

forage fish Forage fish, also called prey fish or bait fish, are small pelagic fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical ocean forage fish feed near the base of the ...

in mariculture.

Status

The sheepshead minnow has a wide range and a large total population, divided up into a number of subpopulations. The total number of individuals seems stable and no particular threats to the fish have been identified, so the IUCN has listed it as being of "

Least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. Th ...

References

{{Taxonbar, from=Q7492475 sheepshead minnow Fish of the Caribbean Fish of the Gulf of Mexico Fish of the Eastern United States Fauna of the Southeastern United States Endangered fish Endangered biota of Mexico Endangered fauna of the United States Endangered fauna of North America Taxa named by Bernard Germain de Lacépède sheepshead minnow