For which five instruments did Schubert compose his "Trout Quintet"?
The "Trout Quintet" is the popular name for Schubert's Piano Quintet in A major. The work was composed in 1819, when he was 22 years old. Rather than using the usual piano quintet line-up of piano and string quartet, Schubert composed the piece for piano, violin, viola, cello and double bass. It was named Trout Quintet because the fourth movement consists of a series of variations on the song "Die Forelle" (Trout).
More Info:
en.m.wikipedia.org