This tank seemed pretty small to me for the grey nurse sharks, white-tip reef sharks and the loggerhead sea turtle kep in here. This is the best I could get of this tank due to overcrowding in the aquarium building.
That square tunnel makes the tank even smaller than it looks, as the inner section is not really usable by the blacktips in here, and in general mostly the upper meter or so can be used by the blacktips.