Here's a good example of a nice indoor tilapia farm. It's a 1000 gallon pool in a basement converted into an aquaculture farm.
He has around 200 fish, which will reach maturity in around 6 months, and he states will end up being around 500 pounds of fish.
Instead of using electric heaters, why not just run a filter hose outside to some black pipe in a solar frame and back in? You will only be using the power already set for the filter (no extra power for heating needed.
Good luck when that pool busts in your basement buddy
Well I wonder what the EPA is going to do when they get wind of it, over abundant use of water?