H.B. Fyfe 
The Klygha [EPUB ebook] 

On a distant planet, a herd of strange aquatic creatures find their minds invaded by the Klygha, an alien explorer who uses them to communicate with a group of visiting Terran scientists. Through the eyes of the Terrans’ cat, the herd witnesses a tense exchange of information between the two space-faring races. As the Klygha grows increasingly desperate to learn the location of the Terrans’ home star, the herd begins to question his motives and their own role in this interstellar drama.