I've got some bluegill inside a 10x16 shed and I think it would do me well to heat the shed if for no other reason than to keep my nitrifiers happy. My question is which is more efficient, heating the air or water?
If its the water, has anyone found the best solution to do so?

I would like to eventually get some tilapia to play with but I would need to know what sort of cost per month I'd be looking at before I commit to future ideas. The plants are currently in the shed as well but I'm attaching a somewhat midsize greenhouse to it so I can setup some 4x30 troughs for a floating raft scenario. The GH will more than likely only be online for about 7-8 months out of the year, just so you know. I don't currently intend on paying to heat the GH, I'll be doing some experiments with passive solar ideas firstly and see where that leads me.

Thanks for any tips