The Oceanarium is located inside the Pacific Beach Hotel in Waikiki. It's a 280,000 gallon tank that soars three stories high, visible from all three hotel restaurants. I took my husband here for a special Father's Day dinner and the kids were mesmerized by the tank the entire time. It's breath-taking, especially if you get to sit next to the massive tank. Depicting a typical reef community, it is the home to 400 fish and 70 marine species.