I'm going to make a little 5 gallon water jug version with my daughter... She wants fish and I don't want to clean a tank. The big setups with tilapia are pretty cool. You grow duckweed to feed the fish, rotate the fish through tanks based on age... last tank is your actual food fish.
It's an artificial marsh. It's easy to make one in Louisiana. Just damn up a ditch in your yard and let the water stand. Aquatic plants will appear. Crawfish, frogs, and turtles will find it. You may have to put in some minnows. Voila! Aquaponics. Mosquitoes will love it and will repel you but will attract birds, which your cat will love.
Standing water works for some plants, bust most need dry roots. Most are setup with a bell valve that allows the grow medium to be soaked and dry on a cycle.