best and easiest thing to do is call the wildlife reserves and they would come pick them up from your house and most likely be able to identify it for you as well..I am not so sure that you would want to house that thing being that it is already HUGE and will be eating plenty I am sure and I don't think that tank you have it in is going to hold that for long.
Creepy..I wouldn't be going back to that lake anymore lol *clucks like a chicken AGAIN*