a pretty kettle of fish

pretty kettle of fish

A difficult or awkward situation; a mess. Primarily heard in US. Well, that's a pretty kettle of fish. I thought I paid the credit card bill, but it turns out that I missed the due date by a week.
See also: fish, kettle, of, pretty
Farlex Dictionary of Idioms.

a pretty kettle of fish

or

a fine kettle of fish

BRITISH, OLD-FASHIONED
If you describe a situation as a pretty kettle of fish or a fine kettle of fish, you mean that it is difficult or unpleasant. Well, this is a pretty kettle of fish, as Queen Mary said. Note: `Kettle' in these expressions may come from `kiddle'. Kiddles were baskets or nets which were laid in streams and rivers to catch fish. Alternatively, `kettle' may refer to a fish kettle, which is a long narrow saucepan that is used for cooking fish.
See also: fish, kettle, of, pretty
Collins COBUILD Idioms Dictionary, 3rd ed.

a pretty (or fine) kettle of fish

an awkward state of affairs. informal
In late 18th-century Scotland, a kettle of fish was a large saucepan of fish, typically freshly caught salmon, cooked at Scottish picnics, and the term was also applied to the picnic itself. By the mid 18th century, the novelist Henry Fielding was using the phrase to mean ‘a muddle’.
See also: fish, kettle, of, pretty
Farlex Partner Idioms Dictionary

kettle of fish, a fine/pretty

A messy predicament. This term is believed to come from a Scottish custom of holding a riverside picnic, itself called a “kettle of fish,” where freshly caught live salmon are thrown into a kettle boiling over an open fire and then are eaten out of hand, definitely a messy procedure. Sir Walter Scott described just such a picnic in St. Ronan’s Well (1824), but the transfer to other kinds of messy predicament had already occurred in the early eighteenth century. The term appears in Henry Fielding’s Joseph Andrews (1742) and works by Dickens, Hardy, Shaw, and many others, but it may now be dying out, at least in America.
See also: fine, kettle, of, pretty
The Dictionary of Clichés by Christine Ammer
See also:
  • fine kettle of fish
  • kettle of fish
  • be (batting) on a sticky wicket
  • a sticky situation
  • a sticky wicket
  • kettle of fish, a fine/pretty
  • pretty kettle of fish
  • a tough spot
  • a tight corner
  • be like a spare prick at a wedding