Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Controlling Grass

JPWS, it's not grass and its definitely not filamentous algae. You could stock 2-3 Triploid Grass Carp to eat it, or you could try a chemical herbicide to treat it. For a better ID you could go to TAMU Aquaplant and look at their submerged plant ID page. They will list treatment options once you find the correct plant.