The kids were entranced- I think there was something about seeing it eating the fish that somehow made it real, and not something to be feared. Most kids are concerned about snakes, and are determined to tell me about the 'water moccasins' that live in our ponds and streams. I'm not sure they always believe me when I tell them that we don't have water moccasins here in the Upstate, only in the lower parts of South Carolina.
We do have copperheads, but it would take effort to see one in the heavily visited parts of the Garden, since they're quite shy, and readily sense us coming.
My retired elementary science teacher friend who was helping me with the program, thought the female, the larger of the two, might be reproductive; Northern water snakes produce a single litter of live young each year after a 3-5 month gestation period, bearing up to 30 young snakes up to 6cm long. These young snakes are independent at birth. This was the smaller one (presumably the male) -- in a close-up view.