Looks like good ol' FA (Filamentous Algae) to me. Grass carp will eat it. A better solution though is to treat the pond with something to kill it, i.e. Reward mixed with Cutrine Plus, treating a portion at a time so it doesn't take up too much DO while dying; and then begin a fertilization program which will not only prevent the FA from recurring but will also give you a better food chain and faster growth for all of your fish.
If the FA is only growing around the edges of the pond, you could fertilize now and skip treating the FA. It briefly might grow more, but once the fertilizer produces a plankton bloom, the bloom will cut out the sunlight from penetrating through the water and the FA will begin to die off.
Another reason this method is better than grass carp is that if you ever plan on installing an automatic feeder or feeders on the pond, the grass carp will monopolize the food and eat you out of house and home; when they get big they'll bully bluegill away from the food so the latter get very little of it.
