Fathead, Tuffy
Fathead minnow (Pimephales promelas), also known as fathead or tuffy, is a species of temperate freshwater fish belonging to the genus Pimephales of the cyprinid family. The natural geographic range extends throughout much of North America, from central Canada south along the Rockies to Texas, and east to Virginia and the Northeastern United States. This minnow has also been introduced to many other areas via bait bucket releases. Its golden, or xanthic, strain, known as the rosy-red minnow, is a very common feeder fish sold in the United States and Canada. This fish is best known for producing Schreckstoff (a distress signal).
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HerbivoreA herbivore is an animal anatomically and physiologically adapted to eating plant material, for example, foliage, for the main component of its die...
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OmnivoreAn 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 ani...
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CarnivoreA carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of a...
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Filter feederAl
AlgivoreAn algivore is a common name for many bottom-dwelling or algae-eating species that feed on algae.
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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PolygynandryPolygynandry is a mating system in which both males and females have multiple mating partners during a breeding season.
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Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withThe fathead minnow in its wild form is generally dull olive-grey in appearance, with a dusky stripe extending along the back and side, and a lighter belly. There is a dusky blotch midway on the dorsal fin. Breeding males acquire a large, grey fleshy growth on the nape, as well as approximately 16 white breeding tubercles on the snout.
Typical total lengths are between 7 and 10 cm (2.8 and 3.9 in).
Fathead minnows are distributed across North America from Chihuahua, Mexico, north to the Maritime Provinces and Great Slave Lake drainage of Canada and have been introduced to Atlantic and Pacific coastal drainage basins in the United States. Their tolerance for multiple environmental conditions, characteristics of their life history, and their popularity as bait species contribute to their widespread distribution. The fathead minnow is quite tolerant of turbid, low-oxygen water and can most commonly be found in small lakes, ponds, and wetlands. They can also be found in larger lakes, streams, and other habitats, as well.
Fathead minnows are omnivores that are categorized as Benthic filter feeders, sifting through dirt and silt to find food. The carnivorous portion of their diet is made up of mainly insects, crustaceans, other aquatic invertebrates, and zooplankton. The herbivorous portion of their diet is primarily made up of algae and phytoplankton. Fathead minnows will also feed on bottom detritus.
Fathead minnows are a largely preyed upon fish that is eaten by mainly piscivorous fish such as Largemouth Bass, Northern Pike, Yellow Perch, Walleye, and various other types of fish.
In the fathead minnow, the female supplies the eggs and the male cares for them until they hatch. The male defends a nest as females pass by and spawn eggs to be cared for by the male. In choosing a nest site, the newly reproductive male fathead minnow tends to take over the nest site of a parental male and evicting its resident rather than occupying an empty one. Also, when given the choice between different unguarded nest sites, it will usually choose the one that already contains eggs. The newer and more numerous the eggs are in the nest site, the more likely the current male is to be challenged by the newcomer. The new male will care for the old male's eggs, a behavior called allopaternal care. Paternal care of the eggs by the male includes rubbing the dorsal pad of mucus-secreting cells, which aerates the eggs and may help prevent disease; removing of diseased eggs from the clutch; and defending the clutch from egg predators, which include animals such as crayfish. This has been shown to increase the survival of the eggs, probably because the newer male is fitter and better able to protect them than the former. Egg survival and parental care behaviors also increase as the clutch size increases. Females also prefer to spawn with males that already have eggs in their nest sites, and the more the better. A male fathead minnow defends the nest site for about three to five weeks at a time, thus continual turnover of new males in the population occurs. The cost of allopaternal care is relatively small because fathead minnow eggs hatch in about five days, while the males can maintain a nest for about three to five weeks; thus, only a small proportion of the eggs that the male takes care of will ever have been adopted.
The main spawning season of the fathead minnow is from June through July, and they are in good spawning condition from mid-May to early August. In males, tubercles occur from mid-May to early August with peak development going from June to July, at the same time as other indicators of reproductive condition. In males, epidermal thickness is significantly higher between mid July and early August, but it stays constant in females. Mucous cell counts also rise in males during the breeding season, but it stays constant in females. The chemical alarm signal in the epidermal cells also drops to almost zero in males during the breeding season.
Fathead minnows are fractional spawners, meaning they begin spawning when water temperatures approach 18 °C (64 °F) and continue until they drop below that temperature in late summer. Fractional spawning can result in 16 to 26 spawning events per female and an annual fecundity of 6,800 to 10,600 eggs per female. Juveniles display rapid growth, reaching 45–50 mm (1.8–2.0 in) total length in 90 days, and most fathead minnows die after spawning by the age of one year.
Spawning can be affected by artificial estrogen, which can get from oral contraceptive pills into lakes via wastewater. Artificial estrogen feminizes male fathead minnows such that they produce vitellogenin, a protein involved in oocyte maturation, and alters oogenesis in female fathead minnows. Chronic exposure to EE, an artificial estrogen used in oral contraceptive pills, led to the collapse of the population due to reduced spawning in a seven-year whole-ecosystem study at the Experimental Lakes Area in Ontario, Canada.
The fathead has been very commonly used as a baitfish, and more recently has emerged in the aquarium trade as the rosy-red minnow. This colour morph was discovered in several Arkansas breeding farms in 1985. Both sexes of this strain have a rosy-golden body and fins and may express dark splotches of wild-type fathead coloration, and are sold in pet shops primarily as feeder fish. They can also be used in home aquariums as pets.
The fathead's invasive status in Europe is cited as the main cause for the spread of enteric redmouth disease among trout and eels there. Established feral populations have been found in France (in 1991), Flanders in Belgium (1995), the Netherlands (2008) and Germany (2015). A small UK population, first discovered in 2008, was declared eradicated the same year.
Generally only the rosy-red variety is sold in pet shops (though very often several wild types come in with each shipment), and is summarily the most likely to be found in an aquarium. These fish are social, active, and moderately hardy. Like most cyprinids, they will accept almost any type of food. They can be bred in an aquarium, and the fathead minnow is one of the only cyprinids that protects its eggs in the nest (carried out by the male). Fatheads will live about two years if they have spawned, but significantly longer (potentially up to four years) if they have not.
The fish can be found at many pet stores as a feeder fish under the name "rosy-red minnow". In an aquarium the fish needs to be in a school (at least 5 or 6) or it tends to be territorial but will not nip fins but instead will ram its head into other species of fish and briefly chase them.
These fish prefer a temperature of 10–21 °C (50–70 °F) and a pH range of 7.0 – 7.5.
