Not quite sure what ya mean by that comment? Do ya also have some perch that are strictly grown indoors with water temp. controlled also? Hmmm. gets me thinking! 
I started bringing in some young of year feed trained perch that I had hatched and feed trained in a pond this winter into one of two recirculating aquaculture systems I build for the basement. That way I get a few more inches on them over the winter before planting them into the two outside ponds in the spring. There's virtually no growth under the ice in the winter so this allows me to get them up to size a little faster.
If you're interested, my system is modeled after the system in the following book that is available on Amazon.com for about $25.00 by Steven Van Gorder. Everything you need to build the system is available at a local building supply store except for polystyrene plastic sheets which are available at plastic supplier.
If anyone is interested in building one I'd be happy to help. You could easily hold and feed a 100 lbs. of minnows in one of these systems. Probably spawn them in another tank.
My tanks are only about 6 foot vs. the 12' swimming pool in the book, and I've made some modifications, as in putting the rotating biofilter in a separate tank vs. in the fish tank itself. I also made a center drain and spray bar that makes the tank self cleaning (the spray bar causes the water to rotate with a circular flow and automatically removes feces and uneaten feed down the center drain).
If anyone is interested in building one I'd be happy to help. You could easily hold and feed a 100 lbs. of minnows in one of these systems.
Original set up before moving the biofilter out of the fish tank and doing some modifications. A small pump pulls water from the top of the clarifier tank to turn the rotating biofilter by dropping water on baffles in the center of the drum. The rotating biofilter has 600 square feet of surface area for nitrifying bacteria to grow on.
A view of the clarifier which is nothing more than a 55 gallon drum packed with deer fence netting to collect suspended and settleable solids from the fish tank. A siphon made of PVC perpetually pulls in fish tank water to the bottom.
If you curious what the iron tank is on the right it's an iron filter I rented. However I wasn't very impressed and built a mechanical iron filter myself which was simply two 55 gallon drums side by side with the water being pumped to one and going back to the other via a siphon. In one drum was filter material where the iron got trapped in. Crystal clear water in 24 hrs.!
This may look complicated to some of you but it's really a simple concept. Basically a large scale aquarium. If I can do it anyone can as I can be mechanically challenged at times. The hardest part was building the biofilter as it was a PITA to cut the fiberglass roofing plates and line them up!
