With the limitations of healthy soil in urban areas, aquaponics is a fast-growing alternative to cultivating produce and protein in cities. Aquaponics is a system of growing crops and fish together in a recirculating water system. Crops are grown in water coming from holding tanks full of fish. The nutrient dense waste is filtered out of the water by the crops and put back into the tanks. The following resources explain the principles and design of aquaponics, as well as provide details on national workshops and trainings.