In the deepest water is the best fishing.

The image suggests that the most rewarding prospects are not always found in the easiest or most obvious place. A better result may call for looking beyond what is readily accessible.

It encourages a person to pursue a promising but more demanding path rather than settle for a convenient option. It does not imply that difficulty alone makes an undertaking worthwhile.

Use it to encourage a more searching approach when someone is choosing between an easy option and a less accessible one that may offer greater rewards. It suits decisions about where to direct effort, without promising success.