if there is I'd love to know what it is too. I cant think of any that meets all the criterion. You could net the pond before leaf fall to cllect all those that do drop. and then you can plant any climber such as clematis/honeysuckle etc.

how about winter jasmine or ceanothus, both are evergreen but you would still get some leaves and flowers

I personally would not grow anything to go over a pond with fish in it. Regardless you are going to get leaves and flower blooms going into your pond which will then need cleaning out thus disrupting your fish.

i have that split bamboo on a roll over a pagoda with an ornimentle grape vine over it.it looks lovley and because of the bamboo and the size of the leaves i just dont get many in the pond.

All plants shed leaves - even evergreens, so unless you net the pond, you're going to get leaves falling into it.

bamboo is right but get a net etc youl be ok . mine is fine.