Kyven Zickerman, 13, explains his aquaponics experiment to fellow students during a Tucson Waldorf School open house. The event was May 10 at the school, 3605 E. River Road. Zickerman grew thyme in the container above while raising fish below in the tank, he said. He would feed the fish, then the nutrients from their waste would be used to feed the plant. Then the water fed to the plant would return to the tank.