At first blush, this seems to make no sense at all. A fine kettle of fish? Who puts fish in a kettle anyway? Isn’t a kettle for tea? Fish tea, anyone?`
To understand the phrase, you need a bit of history. The Scotts used a cooking device that they called a kettle to poach fish. A kettle of fish makes sense from that perspective. At some point, however, calling it a “fine kettle of fish” came to mean quite a mess. Because of the bones? That we do not know. But a fine kettle of fish is in fact, quite a messy situation.
And while we are at this, I used the word “poach”. Poaching was stealing game from the lord’s property. It was punishable by death in some cases. And yet it is also a cooking method – throwing something into simmering water. Huh?
The word comes from the french – and poaching originally meant putting something into a bag (pochier). Hence the stealing idea. You sneak the pheasant into a bag and get the hell out of there! Poaching as a cooking technique originally assumed a bag as well. It might make some sense for eggs. When you poach an egg, the white forms a sort of pocket around the yolk. So you are putting the yolk in a pocket. And poached fish? Err … I’ll get back to you on that one!
MEA CULPA! Note the correction in the comments! It was not just the Scotts who used a kettle!