It occurs in fish at the time of reproduction and ends after the sexual products are washed out. Accompanied by the appearance of a wedding dress.

Usually occurs in specific areas (spawning grounds). Many fish show mating habits during spawning. Some fish (migratory fish) move from the sea to rivers (salmonids, sturgeons) or from rivers to the sea (river eels) to spawn. Fishing may be prohibited during the spawning season. In some groups (e.g. salmonids), the parents die after spawning. Some groups of fish (particularly many perch) show concern for their offspring by protecting the eggs and the larvae that develop from them. Members of the cichlid family also protect their young. However, most fish species do not care for their offspring and will eat their own eggs in the aquarium.