two things that don't go together; mismatched pair
Idiomatic expression likening a mismatched combination to serving loach soup with kintsuba (a sweet bean jelly). Used for incongruous pairings, often humorously.
See also: 金鍔 (きんつば)
His suit with sandals is exactly like pairing loach soup with kintsuba — two things that don't go together.
Kintsuba is a sweet confection; the idiom contrasts it with savory loach soup to highlight a mismatch.
Standard kanji spelling for the full idiomatic phrase.
Mixed kana-kanji spelling; どじょう is often written in kana.
From the incongruous image of serving kintsuba (a sweet bean jelly) alongside dojō-jiru (loach soup), a savory dish. The exact origin is uncertain, but it is a traditional Japanese idiom for mismatched pairings.