Common minnow

The Eurasian minnow, often referred to as the common minnow, is a small freshwater fish belonging to the carp family, Cyprinidae. These fish are widespread across Eurasia, particularly in cool streams, well-oxygenated lakes, and ponds. They are known for their social behavior, frequently forming large groups called shoals.

A common minnow typically grows to about 14 cm in length. They can be identified by their spine and soft-rayed dorsal and anal fins, a lateral line that extends past the anal fin, and vertically elongated blotches on their bodies. Minnows inhabit regions of northern Eurasia, from Ireland to Korea, favoring cold, oxygen-rich waters where they often coexist with salmon.

Minnows are adept at staying safe. They band together in shoals to evade predators and locate food more efficiently. Intriguingly, they release a specific substance to warn others of impending danger, a behavior that displays a form of altruism. Depending on their habitat, they adjust their group behaviors to handle threats and even inspect potential predators.

Breeding minnows in a home aquarium is quite feasible, but they do have particular requirements. They thrive in cold, well-oxygenated water with a good current, a gravel substrate, and clean conditions. During breeding, males exhibit color changes and perform courtship rituals, subsequently guarding the eggs until they hatch. The fry, or baby minnows, start out consuming tiny organisms like infusoria and algae before progressing to slightly larger prey as they grow.