Parental care is a fundamental aspect of the life histories of numerous vertebrate taxa, including fishes, amphibians, reptiles, birds, and mammals. While the ultimate objective of parental investment in offspring care is to maximize survival of progeny, differences in modes of parental care among species are numerous and presumed to arise from tradeoffs in the benefits for offspring survival versus the costs to the parent. The singular benefit of parental care is increased offspring survival. Guarding parents act to clean debris from eggs and increase oxygen levels by fanning the eggs with fins. Filial cannibalism, the consumption of eggs by parents, has been documented in some species. Evidence for antimicrobial parental care in fishes is not restricted to species that guard eggs deposited on the substrate. The study of parental care in fishes in an evolutionary context has yielded an understanding of the potential factors responsible for transitions to male, female, and biparental care from ancestors exhibiting no parental care.