That round tank with the bamboos used to be WAY overstocked. I know this sounds wacky but the last time I went with my wife (February?) there were almost if not more than 20 of those guys in there. My wife went back with my son and her friend last month and said there were only about 5 left. Hopefully this is beacuse they sent them to other aquariums or back into the wild. I'd hate to think of the "National" aquarium as using bad judgement in tank stocking.