As It's a little bit expensive for traveler and there are a lot of aquarium every country, I don't recommend here as must-sightseeing. But, you want really meet fish friends with ocean tunnel, you can try to go there. It is so foolish to pay totally price, 24,000 won, you have to find discount coupon in trazy or other sites. The ticket is expensive so, company sometimes hold the event to attract customers by offering discount coupon. In conclusion, you have to visit travel homepage or busan aquarium homepage in order to check whether they offer cheaper ticket!