The Word Den has neglected military matters until now.
Sadly I have no tales to tell of trained shivers of killer sharks, or hovers of spy-trout. But it was fish that saw off the Spanish Armada in 1588.
Well, it was largely the weather, actually, but the plan was all about fish.
The English knew that if the Spanish (or the French - England had annoyed rather a lot of her neighbours) decided to invade, they would have to come by ship. And to see off these enemy ships the English needed trained sailors.
And what is the best way of training sailors? Being out on a boat. And, really, while they were out there it was felt they might as well do something useful and catch some fish, and then the government wouldn't even have to pay them.
So a crafty law was passed which required everyone to eat fish on a Friday and a Saturday. This gave the fishing industry a big boost, and England survived undefeated.
(That was mostly because a storm got up and blew the Armada of enemy ships all over the place, but hey, the best laid plans...)
1588 was a long time ago, but fish are still used in sea battles: well, tin fish, are, anyway. A tin fish is another word for a torpedo.
Spot the frippet: fish. This word is from the Old English fisc, and before that from the Latin piscis.