Life in water and life on land pose unique challenges for animals living in each type of environment. Yet amphibious fishes, those that emerse and survive out of water as part of their natural life-history, straddle life in both worlds. Consequently, their physiology must exhibit sufficient plasticity to balance trade-offs and allow survival in both types of environments. The ability to effectively transport oxygen and remove respiratory waste products is critical to the maintenance of life - the central question addressed in my research asks how respiratory plasticity in amphibious fishes allows effective respiration in both aquatic and terrestrial habitats. Results from this work will fill a gap in knowledge not only for extant amphibious fish species but may also provide evolutionary clues about one of the major evolutionary steps - the expansion of life from water to land.