Hippopotamus welfare in zoos depends critically on access to adequate aquatic environments, and modern pool design standards reflect growing understanding of their specific needs.
Hippo welfare centres on water access — without adequate pool depth for submersion and swimming, hippos cannot maintain thermoregulation, skin health, or express fundamental natural behaviours. Many older zoo facilities have pools that are too shallow for proper submersion or too small to allow movement. The infrastructure required for truly adequate hippo pools — depth of at least 1.5 metres with significantly larger preferred, appropriate filtration, thermal management, and adjacent land areas — represents a substantial investment. Facilities unable or unwilling to make this investment should consider whether housing hippos is ethically justifiable. Modern accreditation standards increasingly reflect this reality, with minimum pool specifications that better align with hippo welfare requirements.