the way in which aquatic creatures die due to being out of the water? When we can't get air, we asphyxiate; what do they do?
I think you could still say 'asphyxiate' Jackie
as they die from lack of oxygen, not lack of water. They need to be in the water to breathe.
asphyxia
1706, "stoppage of pulse," from Modern Latin, from Gk. asphyxia "stopping of the pulse," from a- "not" + sphyzein "to throb." The current sense of "suffocation" is from 1778, but it is a "curious infelicity of etymology" [OED] since victims of suffocation have a pulse for some time after breathing has stopped.