Garden Fountain Pumps How Can I Power A Small Fountain/pump 50 Ft From An Outlet?

How can I power a small fountain/pump 50 ft from an outlet? - garden fountain pumps

I am a garden of 25-30 liter water tank with a pair of goldfish. I want a filter / fountains, but that's 50 "coming from the outlet. A budget of solar energy, so I want to run an extension cord out of the subway. Years ago my father had two 100 'ropes to the outside without any protection between the two houses and there for 5 years without any problems. But my situation is somewhat different. It is underground, and almost always lead. Is this feasible? If so, how do I protect the nozzle from the pump? Duct Tape?
Thank you!