Funnily, I'd say the opposite. The background is quite busy and sometimes the turtle's head is directly in front one of those rod/pipe things in the water (are those bamboo stalks?) I'd suggest a lower angle, like in #3 and 4, and a shallower depth of field to isolate the turtles a bit more. Watch the background and try to get the heads more against the water so it doesn't get lost.
The light is tricky - they come out when the sun is strong but that's when the light is harsh. I'd try to go as late in the afternoon as possible while they're still out.