“If you can’t see water, don’t order fish”

‘If you can’t see water, don’t order fish” means that fish won’t be fresh if you’re not near the source. For example, Florida might be a better state to eat seafood in than Oklahoma. The origin of the saying is unknown.
 
 
Google Books
Second Wind;
Handbook for Happy Retirement
By Philip J. Kelly
Published by McIlvaine Pub. Co.
1972
Pg. 55:
Grandma and Grandpa moved away, far away from any water. Once again, they’re on dry land and they never order fish in a restaurant or buy any fish in a store.
 
Google Books
The Traveling Curmudgeon:
Irreverent Notes, Quotes, and Anecdotes on Dismal Destinations, Excess Baggage, the Full Upright Position, and Other Reasons Not to Go There
By Jon Winokur
Published by Sasquatch Books
2003
Pg. 97:
If you can’t see water, don’t order fish.
ANONYMOUS
 
Google Books
Old West Tales, Good Men, Bad Men, Lawmen
By Clifford Caldwell
Published by Lulu.com
2007
Pg. 68:
He said “look out the window, do you see water…”? I did so, and did not see any water at all as we were in Iowa at the time. He then offers “well then, I guess it’s beef…never order fish if you can’t see the water”.
 
Europe Top Restaurants - Zagat Survey
Fish
U Luzického semináre 42 Prague, Czech Republic 118 00
(...)
Reviewed by bo1494374 on 06/04/2008.
as they always say ... if you can’t see the water, don’t order fish.