In Strange Waters - O'Ceagan Saga, #2.5

For a shape shifter stranded on a distant world, water is life itself; the main thing that makes his self-imposed exile tolerable. But Dari soon learns the waters of Erinnua are not like the seas of Earth. The sea life appears twisted and distorted. Swimming in it feels unnatural to his water horse form as he finds it disturbing and dangerous. Even the dominant underwater species may be suffering from the effects of a terrible human-caused accident.
In fact, all life on the planet may be at risk if what he fears is true. Can Dari convince the human colonists of the danger and work with them to prevent the disaster threatening their world? Set in the same universe as "O'Ceagan's Legacy, " this tale takes the reader on an adventure with the shape-shifting puca as he explores his new home.