You could keep paddlefish locally in theory my uncles landlord did something that might fit the problem of feeding a filter feeder. Biasically what you would do is build a large square or rectangle pond that is relativly deep, keep in mind you would have to do this somwhat close to a moving stream. after you've built the pond itself you make a wide deep trench from the stream to your pond, and back out the other side to rejoin the stream. you would have to keep the entrance and exits of your pond grated to prevent the fish escapin the pond. The zooplankton in the stream would flow in to your pond and would sustain one or two paddlefish if supplemented with a slow sinking food. this is just a idea and has it's flaws but it my just work and i've seen it done with out paddle fish in the pond. i'd love to hear any dissagrements or constructive critizim.