In order to bring water from the fish tank up to the top of the Farm Fountain you will need a pond pump.
This one was purchased at Lowes for the discounted price
                        of $45 due to it being a floor model with a missing sprayer
                        top. Normally it is $99, so we were happy. Pay attention
                        to how high it can lift the water, as well as how many
                        GPH (gallons per hour) it can pump. 
                        
                        This one pumps 300 GPH and it has no problem lifting
                        enough water up 6 feet high.