Hi there.No,a pump and filter would be the worst possible thing you could put in a wildlife pond because the pump could well chew up a newt(I have seen it happen) or a tadpole.They like still water anyway.The only thing I would advise,as well as lots of plants to prevent algae problems,is that you make sure the amphibians can get out of the pond easily.Pre fabricated ponds are generally designed for fish and don't have the gentle sloping sides that a dug and lined pond would have.Generally there will be a shelf and you could either put a granite rock or slate slab on it so that frogs could climb onto it and then jump out,or a plant pot,with a marginal plant in,so that the edge reaches near the top.Once you get frogs inhabiting your pond,you will soon find out the best way of ensuring they get out.
The other problem you need to guard against is if a hedgehog falls in;again if you create an area accessible to the edge it should be O.K. Just use ordinary garden soil to plant the weed and plants in,not aquatic compost.
