I always wanted to checked out Osaka Aquarium Kaiyukan since years ago but only now we have the chance. Sadly we were just went to Singapore Oceanarium, which is newer and had huge collections of marine life especially a lot more Jelly Fishes than Osaka. A Few differences Osaka has Whales, Penguins and Sea Lion, and Seal. Singapore does not have that. The crowds in Osaka Kaiyukan is really too crowded.