What do stickle back fish eat?

Assorted invertebrate aquatic life, they are actually voracious little predators for their size! If they were larger, they'd probably be challengers to pike, zander and wallleye. On the flipside, the male stickleback is a devoted father to his young, and builds and defends (to the death) a nest for them, which is unusual in fish species, most lay their eggs and go.