As fascinating as the reproductive life of seahorses is, there has been little science devoted to the emotional or mental state of these fishes, and no research on seahorses pre- or postpartum. Considering what we know of biochemical changes that occur in higher vertebrate brains after giving birth and during PPD, it would seem logical to explore hormone and cortisol levels in reproductive and non-reproductive seahorses as a first step. This has not be researched to date and so from a biochemical standpoint, we just don’t know.

If we consider postpartum depression as it relates to parental investment in humans, it can be argued that if mothers, or now we are learning, fathers, feel that they do not have the support network or ability to raise a child, they may be prone to PPD, thinking they cannot succeed at the task at hand or their situation is not conducive to success. Unlike other species, male seahorses give birth to several hundreds of fry in one brood and are ready to mate and conceive again in as little as 24 hours. As is common in the fish world, parental care of young is not present in seahorses. Fry, sometimes less than .5cm in length, are birthed from the male’s pouch and set upon the ocean’s currents to find their own way. The investment needed to raise young [or] the ability to perform the task at hand is not present when parental care is not provided. It could be argued then, that male seahorses probably do not exhibit postpartum depression or, at the very least, are not prone to it.

Mental health is a complicated science. Many factors - behavioral, environmental, genetic, and biochemical - may play a part in a predisposition to or occurrence of mental illness. Until we are clear about our understanding of PPD, if, or how, it may manifest itself across taxonomic lines, and sound scientific research confirms our understanding, we should be cautious not to anthropomorphize the condition in other species