Here is a pond I looked at yesterday infested with fanwort, also called cabomba. Fanwort is a submerged, perennial weed. The submerged leaves are opposite, and attached by a single petiole. Above the petiole they form a “fan-shaped” leaf. Fanwort also has a small white to pink flower which forms on the tip of the stem and stands just above the surface. One of my photos shows the flowers across the surface of the water.
UGA Extension Aquatic Scientist Dr. Gary Burtle says diquat has been used successfully on fanwort. Fluridone can also be used if water flow through the pond is minimal. This pond has dense weed growth, so repeat treatment will be advisable.
Stock grass carp at 10 per infested acre following chemical application in order to obtain long term control.
Here is a link to more information on biology of Fanwort.