Dave --
You can indeed use grass carp in Virginia -- they allow the use of the triploid fish, with permits.
Believe it or not, this little pond has 8 grass carp in it already. A former owner put them in. And they're HUGE. In fact, that's the problem. From the literauture I've been able to turn up, grass carp will indeed crop down chara ... until they're about 18"-20" long. Then, for some reason, they seem to lost their taste for it and switch to other plants. I have no idea what they feed on in my pond. But the very smallest is 30" if it's an inch! And they are all skittish as can be!
My best guess about their current diet is the little shoots at the base of cattails, beacuse I find an unually high number of cattail roots floating in the pond. But that's only a guess.
If I ever catch one, the very first thing I'll do is examine its belly to see if I can identify what they feed on. But I don't know how to catch them! I had foul-hooked one once about two years ago -- using a small fly, intended for trout, I accidentally hooked the caudal fin of a grass carp. WOW. A memorable, but brief "fight": it emptied my fly reel in about three seconds flat.
I may have to ask "catmandoo" from up in Hampshire County, WV, to come down and give me a lesson -- he caught a huge grass carp from his pond and posted a great picture back on Oct. 6. I've even contemplated investing in bow-fishing gear ... but then I think, we'll those big old things are sure fun to watch, and visitors from the city always mistake them for the trout I grow ... now that's really fun!
