Post a picture if you can (and are so inclined). I haven't seen a one yet here although I understand we have plenty down on the lake and the creeks. We have just one small tank on our property though, and this part of Texas is considerably drier than Mississippi I understand.
Tell your hubby to be careful though, from what I read cottonmouths are about the most aggressive of american venomous snakes. I think I prefer our shy little copperheads.