I keep Diamondback terrapins, I have a fence surrounding my pond about 3.5 feet tall it is out of welded wire, with poultry netting at ground level about a foot tall buried 6” in the ground. Don’t really notice the wire mesh, I also have wide weave netting over the top of the pond to keep predators out, a lesson learned the hard way ( lost some terrapins to a hawk).
You will have to protect them from predators ( raccoons , foxes, birds) because sooner or later one will get the turtle especially a smaller turtle. I like the terrapins as they are strictly carnivores and don’t destroy plants like the painted turtles and sliders do.
You should provide floating logs for basking areas, as they don’t like to bask on the shoreline because of predators.
