The aquarium is privately owned and absolutely one of my favorites after visiting it. I have been to the Georgia Aquarium, the Aquarium up in Boston, The Seattle Aquarium and now the Maui Aquarium. All have great exhibits which I enjoyed while learning about the local biopes. The Maui aquarium is especially interesting because it is almost entirely devoted to the local reef. There is so much coral there it makes your head spin. Great exhibits about whales and of course the now requisite underwater domed walk through the main tank.
Well worth the admission price but don't do what my wife and I did. Allow yourself more than two hours to tour the place.
http://www.mauioceancenter.com/
-Ken