Carp is great to eat, especially when it's that small. Anything more than 5lbs, it's a bit too fatty. Just make sure to remove the mud veins from the meat before eating. Smoked meat, then stir fried with green scallions is the ticket, seasoned with lemon pepper, garlic, and olive oil, with a bit of sea salt to make the taste comes alive.
As for Lake Hemet, I wouldn't eat out of that lake. Same goes for Canyon Lake, Lake Menifee, or Lake Skinner, especially for carp that exceed more than 4lbs. Anything between 2 to 3lbs, good to go.