Nürnberg Zoo - Manatees

There are only five dugons in captivity

wow, it just passed me ( yes I am slow) wiki it.
according to wikipedia there are 6:
two in toba aquarium, 1 in singapore, 1 in sea world indonesia and 2 in Sydney aquarium, but I don't trust wikipedia all that much.

and according to the sydney aquarium website, there is 5