you will have to use power solar is to weak and unreliable especialy if your fish rely on it . thats a long way for a pump to push water . when you bye a pump that is rated at say 200 gallons it is actualy rated when the pump is egsactly level with the water level so it is under know stress from pushing water uphill.you could maybe get a water trickle and i mean trickle but i wouldnt do it .

The only solar powered pumps I have seen are the kind that spray a tiny fountain up out of a pond, and and Noseypotter says would provide nothing like the amount of electricity you would need to power a 5 foot high waterfall.

I am sure that what you want to do is possible, but the reason people don't is that it would be much more expensive than to use mains. The reason for this is solar is expensive to install, and requires a decent surface area for a reasonable amount of electricity, which would use up quite a lot of most people's garden area or have to be put on an unsightly mast.

If you are interested in solar power, then the normal way forward would be to use solar power to contribute to your whole household energy bill, which would include the water pump. It starts to make savings after about 5 -10 years when you take the cost of installing it into account.

There are companies that install and advise on solar power like www.heatmyhome.co.uk - this company has a list of questions and answers on its website which might give you more of an idea of what is involved if you are considering it.