Bigger/other fish to fry

This expression means that one has better, more important things to do and first appears in English as “other fish to fry” in Peter Motteux’s c. 1700-1703 translation of Cervantes’ Don Quixote. Cervantes actually wrote, in Spanish of course, “I have other things to do”. Motteux was merely using an expression that was already familiar and idiomatic by 1700. The idiom is therefore much older but no other citation has come to the fore. (Incidentally, a Google search revealed four times as many hits for ‘bigger’ fish to fry than ‘other’ fish to fry.)