People
The fishy glitter in his eye became intensified. He looked like a halibut which had been asked by another halibut to lend it a couple of quid till next Wednesday.
— P.G. Wodehouse • The Word in Season

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The face is compared to a fish being asked for a small loan. That unlikely request gives the fishy stare a comically guarded quality. The exact sum and deadline make the imagined exchange sound ordinary, which sharpens the absurdity of picturing it between halibut.
Context reviewed