Some purchase a net like this: http://www.basspro.com/Bass-Pro-Shop...duct/10205343/
then get an extendable paint pole from your local big box store, to use in place of the handle provided.
Extendable poles come in a variety of lengths.
Just a side note: you will have to make some modifications to the pole end to mate up with the net.
To better control the net, go to the dollar store and purchase a swim noodle, cut a 12 inch length and slide it onto the end of the pole near the net.
This will keep the net on the surface of the water, while reaching out to net the fish.