Having had a huge koi pond for the last 6 years with fish almost 2 feet long that would eat out of my hand & were my pride & joy, & coming home to find out my pumps were off & they were all dead, I would not mess with anything that will take a changc on losing your fish. I had two commerical top quality pumps & although the pumps were fine, the plug they went to went out & without the waterfall & two fountain heads, there was not enough oxygen to keep them alive & they died. Solar does not always work, I have those little solar yard lights that bearly glow. If you have a little pond with little fish that do not need a lot of oxygen, it will probably work. But they need constant flow of water for oxygen, & if you were going to have a filter, I dont think it would have the horsepower it would need to keep all the going.
Good luck. It has been 6 months since my incident, & i cant bring myself to even go in the backyard anymore. We are in the process of moving & i am planning another one with all sorts of fail safes for the next pond. I am not even considering solar myself. But asking a pond specialist would probably be best
Debbie