Since there were so much fish and mammals to see, I decided to post a 1min video as a preview:
As I exit, I spotted this:
It was super tempting to pay 1,000yen for a chance to win a big whale soft-toy but knowing that I can never have such luck, I walked away after taking this video... (save money to eat fish instead haha).
Overall a nice place to visit during rainy days but maybe not on a Sunday unless you have kids, they will love it.
Official website: http://www.kaiyukan.com/language/eng/