Going to a smaller SUMP pump alone will reduce your fountains appearance. The flow will certainly be reduced. You might be able to go to a smaller horsepower pump of a different type and maintain the flow and reduce costs, but without some specs, it is hard to speculate with any amount of certainty.

Your typical fountain pumps and basement sump pumps are centrifugal pumps. SO LONG as your nozzles do not over restrict the water flow, they will run efficient. If your bill is higher than you would like, you can down size your fountain and/or run it less.

Another option is to open up the nozzle orifice and see how you like the fountain. If the bill is still too high, drop the pump size down and possibly reduce the nozzle size to get a further spray.

Fish on!,
Noel