This geometric shape spans up to 2 meters in size and is mastered by the tiny creature called the Japanese puffer fish – with a length of only 12 centimeter. This minuscule fish swirls the sand with his fins and stomach to create a distinctive wave movement and continues this procedure until he has accomplished his circular masterpiece. His threat is the current, which forces him to work without interruption, lasting up to 7-9 days. In addition he willingly decorates the center of the formation with shells and pieces of coral.
This wonderful creation is not merely for the sake of his own well being.
It is an offer to a potential female, who is willing to mate. She is drawn to the perfect mathematical shape, recognizing his strength and therefore perfect genes. The most beautiful part of his revelation is not left unrecognized – the female places her eggs in the center, leaving them for him to fertilize and protect them from potential intruders.
“Nowhere else in nature does an animal construct something as complex and perfect as this.”
Source: (BBC-Earth, Life Story Ep05 – Courtship – Puffer Fish)