The three-spined stickleback is shown. Nest building, zigzag dance, fanning at the nest, sometimes following a female, also short mouth fights, the female swimming into the nest, spawning, the male poking at the rear end of the partner, inseminating the eggs in the nest after the female swims away.

• Heinz Sielmann-Produktion
• Institut für den wissenschaftlichen Film (IWF)