Minnow is a general term used to refer to small freshwater and saltwater fish, especially those used as bait fish

Bait fish

Bait fish are small fish caught for use as bait to attract large predatory fish, particularly game fish. Species used are typically those that are common and breed rapidly, making them easy to catch and in regular supply. Examples of marine bait fish are anchovies, halfbeaks such as ballyhoo, and...

 or for fishing bait

Fishing bait

Fishing bait is any substance used to attract and catch fish, e.g. on the end of a fishing hook, or inside a fish trap. Traditionally, nightcrawlers, insects, and smaller bait fish have been used for this purpose...

. More specifically, it refers to small freshwater fish of the carp

Carp

Carp are various species of oily freshwater fish of the family Cyprinidae, a very large group of fish native to Europe and Asia. The cypriniformes are traditionally grouped with the Characiformes, Siluriformes and Gymnotiformes to create the superorder Ostariophysi, since these groups have certain...

 family.

True minnows

Smaller fish in the subfamily Leuciscinae

Leuciscinae

Leuciscinae, commonly known as true minnows, are a subfamily of small fish belonging to the family Cyprinidae.However, the term minnow is also used as an unspecific term for tiny freshwater and saltwater fish, especially those used as fishing bait....

 are considered to be "true" minnows:

• Bluntnose minnows, fish in the genus Pimephales
  Pimephales
  Pimephales, commonly known as the bluntnose minnows , is a genus of cyprinid fish found in North America. All of the four species are small fish, with P...
  
  
• Cardinal minnows, fish in the genus Tanichthys
  Tanichthys
  Tanichthys is a genus of freshwater fish in the carp family of order Cypriniformes. Until recently, the type species, Tanichthys albonubes, was the only one known. In 2001, however, Freyhof and Herder described a new and very similar species, Tanichthys micagemmae, from the Ben Hai River in...
  
  
• Cheat Minnow Pararhinichthys bowersi
  Cheat minnow
  The cheat minnow is a demersal, freshwater fish endemic to the United States, most commonly found in the Ohio River basin...
  
  
• Cutlips minnows, fish in the genus Exoglossum
  Exoglossum
  Exoglossum is a genus of mound-building freshwater fish. Members are commonly known as cutlips minnows, though the individual species, particularly Exoglossum maxillingua, are also locally known by that name....
  
  
• Desert minnows, fish in the genus Dionda
  Dionda
  Dionda is the genus of desert minnows, small fish belonging to the family Cyprinidae. They are native to the fresh waters or North And Central America...
  
  
• Eurasian minnows, fish in the genus Phoxinus
  Phoxinus
  Phoxinus is a genus of freshwater fish in the carp family of order Cypriniformes. The type species is Phoxinus phoxinus, the Common Minnow. The North American members of this genus are known as daces, and the Old World ones as Eurasian minnows. The latter term is also used specifically for P...
  
  
• Loach Minnow (Rhinichthys cobitis)
• Pikeminnows, fish in the genus Ptychocheilus
  Ptychocheilus
  Squawfish or pikeminnows are cyprinid fish of the genus Ptychocheilus consisting of four species native to western North America. Voracious predators, they are considered an "undesirable" species in many waters. This is largely due to the species' perceived tendency to prey upon small trout and...
  
  
• Pugnose minnows, fish in the genus Opsopoeodus
• Silverjaw minnows, fish in the genus Ericymba
• Silvery minnows, fish in the genus Hybognathus
  Hybognathus
  Hybognathus is a genus of ray-finned fish in the Cyprinidae family. Its members are collectively known as the silvery minnows.- Species :* Hybognathus amarus...
  
  
• Suckermouth minnows, fish in the genus Phenacobius
  Phenacobius
  Phenacobius, the suckermouth minnows, is a genus of cyprinid fishes endemic to the United States. There are currently five described species.- Species :* Phenacobius catostomus D. S...
  
  

Other minnows

Other fish specifically called minnows include

• in the Southern Hemisphere, some fish in the family Galaxiidae, in particular those of genus Galaxias
  Galaxias
  Galaxias is the common name for a large group of smallish, highly successful freshwater fish in the Galaxias genus and Galaxiidae family. Galaxias are restricted to the southern hemisphere, and generally only occur in temperate latitudes; only one species is known from sub-tropical habitat...
  
  
• in Southeast Asia, the danionin
  Danionin
  The danionins are a group of small minnow-type fish belonging to the family Cyprinidae. Members of this group are mostly in the genera Danio and Devario. They are native to the fresh waters of southeast Asia. Many species are brightly coloured and are available as aquarium fish worldwide...
  
  s
• the Drakensberg Minnow
  Drakensberg Minnow
  Drakensberg Minnow is a species of cyprinid fish endemic to the Congo Democratic Republic....
  
   (Barbus aspius) from South Africa
• the Maluti Minnow
  Maluti Minnow
  The Maluti redfin is a ray-finned fish species in the family Cyprinidae. It is colloquially called Maluti minnow, but it is not a true minnow....
  
   (Pseudobarbus quathlambae) from Lesotho
• the Falklands minnow from the Falkland Islands
  Falkland Islands
  The Falkland Islands are an archipelago in the South Atlantic Ocean, located about from the coast of mainland South America. The archipelago consists of East Falkland, West Falkland and 776 lesser islands. The capital, Stanley, is on East Falkland...
  
  
• the Piketop winnow (Belonesox belizanus) are confused for the northern pike
  Northern Pike
  The northern pike , is a species of carnivorous fish of the genus Esox...
  
  , (Esox lucius), also called "Minnow" for the little zize.