fish biting; fish striking; fish taking bait
Refers to the action of a fish biting or taking the bait, often used in fishing contexts.
The fish aren't biting well today.
Aim for the time when the fish are biting well.
Compound of 魚 (fish) + の (possessive particle) + 食い (biting, eating). The exact historical derivation is straightforward; the expression is transparently formed from its components.