kettle of fish

An expression that means 'That's a whole 'nother subject.'

We were going to talk politics, but that's a whole 'nother kettle of fish!

by Curt H June 3, 2008

a diffrent kettle of fish

a different situation or person to be dealt with

Breakfast was a very different kettle of fish here in America.

by Choonmann Sung January 9, 2005