Physiological mechanisms that fishes use to cope with very high or very low pH

Abstract

Generally, fish species are most abundant in aquatic habitats with neutral or near-neutral pH conditions. However, some species can survive extremely high or low pH, conditions which are surprisingly widespread worldwide. This article explores the physiological mechanisms that representative fish species employ to adapt to extreme pH, whether high or low, including key processes like acid-base balance, ammonia excretion, and ion regulation.