Why do archerfish spit water?

Answer: Shooting down insects to eat

Shooting down insects to eat ✓ — Correct! Archerfish hunt insects on leaves above water by spitting precise water jets (up to 6 feet high!) to knock them down. They learn to account for light refraction, angle, and distance. Young fish practice and improve accuracy. Once insects fall into water—snap! It's impressive physics and hunting skill!

Cleaning their gill filters — Wrong. Spitting is for hunting, not hygiene. Archerfish have normal gills and don't need to clean them by spitting externally.

Defending territory boundaries — Wrong. The water jets target insects above water for feeding, not defending against other fish. It's a specialized hunting technique.