 It is also known to occur in crayfish and amphibians.This section is patterned after a classification of the spawning behaviours of fish by Balon (1975, 1984) into reproductive guilds.This classification is based on how the eggs are fertilized (internal or external spawners), where the eggs are deposited (pelagic or benthic spawners), and whether and how the parents look after the eggs after spawning (bearers, guarders and nonguarders).