Foam is Home

If you fish very long an old-timer will remind you on a slower-than-molasses day that "foam is home".  If you find a piece of water with a lot of foam on top you will find the insects that have hatched and the fish that eat them.  The fish also find cover from the long list of predator's above which includes us.

The old-timer's have a way of distilling important pieces of information in only a few words.