re: Heating small outdoor pond?

Seen this done with a home-made solar panel before. Probably way less convenient than buying a heater for it but if you’re like me you’d get a kick out of making one yourself. let me do the best recollection I can here:

Build yourself some wooden frames and a center panel of wood that pivots like a solar panel. Make the panel like 6 feet wide 3-4 feet high. Box in the panel so it’s about a foot deep, leave one side open. Drill an inlet and outlet hole on your box and put in rubber hosing, nylon hosing or cpvc/pvc, your call but i would go with nylon since it’s so malleable and easy to work with. Anyways arrange the tubes so it’s like a radiator, soaking in all the heat it can. Apply a pane of glass to the open side of the box. Put on a water pump of your choosing, run the water pump inlet to the bottom of the pond and the outlet into the panel inlet, panel outlet to waterfall reservoir. A remote thermostatic control should do for controlling the pump and regulating temperatures