  All Rota-Baxter operators of weight zero on split octonion algebra over
a~field of characteristic not 2 are classified up to conjugation by
automorphisms and antiautomorphisms. Thus, the classification of Rota-Baxter
operators on composition algebras is finished. There are two descriptions:
a~common description over arbitratry field of characteristic not 2 and more
accurate description over a~quadratically closed field of characteristic not 2.
