Thanks everyone, glad you like the build.
Haven't really worried about energy, we have the cheapest power in the USA at 3.5 cents per KWH so it won't be much.
We have some T-8 shop lights hanging directly above the pond, not sure how well they will work for lighting, if we don't like it can always rig up some T-5s or LEDs. We are going to be running some 2x4 braces across the top before filling, so we can rig lights up to those braces.