Phoxinus phoxinus
| Phoxinus phoxinus | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Cypriniformes |
| Family: | Cyprinidae |
| Genus: | Phoxinus |
| Species: | P. phoxinus |
| Binomial name | |
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Phoxinus phoxinus (Linnaeus, 1758) |
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The Eurasian minnow,minnow, or common minnow (Phoxinus phoxinus) is a small species of freshwater fish in the carp family Cyprinidae. It is the type species of genus Phoxinus. It is ubiquitous throughout much of Eurasia, from Britain and Spain to eastern Siberia, predominantly in cool (12–20 °C) streams and well-oxygenated lakes and ponds. It is noted for being a gregarious species, shoaling in large numbers.
In Germany the Eurasian minnow is rarely encountered and is a protected species.
Shoaling and schooling behavior of common minnows occur early in their development, as soon as they become capable of swimming. Shoaling behavior then increases and becomes dominant by three to four weeks after its emergence. This behavior generally benefits individual minnows by improving predator avoidance and foraging. However, there are also costs of living in groups such as increased competition for food and risk of infection. Shoaling behavior is modified depending on the situation such as presence of predators or resource availability.
The group formation of common minnows can be explained by the selfish herd effect proposed by W.D. Hamilton. According to the selfish herd theory, a group forms as individuals try to reduce their domain of danger by approaching others and continuously moving toward the center of the group where the risk of predation is the lowest. As the theory predicts, common minnows increase their shoaling behavior in response to increased predation pressure.
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Wikipedia