Ritual: Carp's sake-drinking

One of our readers, a scientist who spent the first half of his life in Japan, tells of a ritual that seems to be not terribly well known or studied. He writes:

This is a strange tradition in some part of Japan which I was not aware of until today, when I saw a report in Yomiuri Shumbun.

Carp — the fish — are made to drink "sake" (Japanese wine) before they are released into a river. People believe this ceremony helps to get rid of evil.