Sticlkebacks are small fish... 2-4 inches long with hard plates on their bodies and sharp spines on their dorsal fins. They put the spines up when someone tries to swallow them, and stick in the throat of their wouldbe predators, until they cough them out.
They are not very pretty most of the year.... but in spring the males turn electric blue on top with bright orange chests.. the females are olive green and swollen with eggs. Males build nests of plants in the bottom of shallow ponds and display their colors in hopes of attracting the females.
Researchers have studied how the male leads the female down to the nest... first leading, then turning as if to chase her away... Apporach and aviodance behavior is what they call it.. He's conflicted between leading the female to the nest and defending the nest. She's conflicted between following mr colorful and fleeing his aggressive teritorial defense.
It's just like real life, what these fish do!