A word of caution...

Don't add crayfish until you have a predator fish population established in the pond that's capable of controlling their numbers.

If you install crayfish without a control species they will eat every single speck of vegetation in your pond.

I had a beautiful stand of APW until I added crayfish. They wiped it out in short order, along with my arrowhead, mud plantain
and pickeral weed. When my HSB and SMB sized up to the point they could swallow adult crayfish the situation started to
improve. The mud plantain and arrowhead have started to come back. I saw a few sprigs of APW back in the spring but the
drought left it high and dry. I'm hoping the winter wet season fills the pond back up to the spillway, or at least gets it close.
If that happens I expect the pondweed will start to make a comeback next year.