If you just see this frame, you would bet the photo was taken in the wild. Looks like a great exhibit (beside the point that colobus or vervet monkeys on the island would fit better then gibbons).
This is a wonderful shot. Many zoo's don't allow them access to deep pools, as such it is a treat to see sitatunga/lechwe/waterbuck in the water. I have, sadly, never been so lucky!