[jester]

Yes, I mentioned that in my urban city in the sky idea a few posts ago, where former water tanks and swimming pools found atop many tall buildings would be converted to aquaculture. And yes, it is quite common to grow multiple things in aquaculture. An example, in the US South where they farm crawfish they also grow rice. Or should I say they raise crawfish in their rice fields yeilding about 2 harvests of the criters before they harvest the rice.

Other mollusks and crustatia can be farmed in similiar conditions, where one may grow water chestnut or cress, cattails and even cranberrys, one could toss in some carp, or even bass or catfish as well as snails and shrimp.

There are a few operations where they grow sturgeon in tanks that are about the size of a larger kiddie pool. And others where prawns are raised in a slightly deeper tank. So, it is entirely possible. Here is one for urban aquaculture: Turning the underground parking garage, or even the basement since these would most likely become flooded anyways into places to grow various water creatures like fish, shrimp and shellfish.

Here is another idea. Simply making an indoor aquarium or even a tank inside, using 1 solid brick wall, wotu either glass or plexiglass and caulk, or just another wall of bricks/cinderblock so you have a space of about 2 or 3 meters by the length of the wall that is say chest high thus allowing you access to fish, clean and refill the tank. A tank that size would also help stabilize the temperature in the room since water tends to absorbe heat and holds it a bit longer.

Another idea is the various cisterns that would be found to hold water could be used to do double duty for aquaculture as well.