Social and reproductive behaviors: Parental care in fishes

Although parental care is not the norm across fish species, it does occur in some fish species with parents defending, cleaning and aerating young, and even sometimes providing food for young. How much care is provided, and which sex provides care, varies across species and is shaped by life history, phylogeny, benefits (increased survival) and costs (decreased survival, growth and mating) for males versus females. As male care is common in fishes and the sex of the caregiver often varies between closely related species, many fish studies have been conducted to test ultimate theories of parental care evolution. In contrast, the physiological mechanisms underlying care in fishes are less well understood with the neuropeptides isotocin, arginine vasotocin, prolactin and galanin emerging as key modulators of parental care behaviors.