Hydrilla is getting out of hand

What would be the permaculture solutions to hydrilla aggressively taking over a pond?

A pond near our farm had a recurring hydrilla problem. The owner stocked triploid grass carp in the pond last spring and the hydrilla disappeared. The cattails and bullrushes seem to be unaffected.

You could use it as free fertilizer in the garden, mulch or compost. Back in Oregon, we used to go to a lot of trouble to get kelp for this purpose! As in trips to the ocean. Our poor car...smelled of seaweed a bit after those trips.

Now I'm attempting to grow azolla in an open tank for this use, too.

But if you don't want a task that takes physical labor, finding something that eats it is a great option.  Ducks and other waterfowl also love hydrilla:
Orlando Sentinel NEws - Hydrilla reduction program doesn't fly with duck hunters

I am curious as to what's feeding it. Is there runoff from any sort of farming field? Some excess nitrogen source?