Let's have fun even on rainy days ♪ Rainy Aqua World starts from June 6th

Together with the creatures related to rain,
Enjoy the rainy season at Aqua World Oarai

The rainy season will soon be upon us, and we will be exhibiting rain-related creatures, perfect for the time when it rains a lot. Enjoy the time unique to the rainy season at Aqua World Oarai, where you can enjoy the whole day indoors even on rainy days!

“Make it rain! ? Aplysia aquarium” is now available

A special aquarium featuring Aplysia, a creature associated with rain, will appear!


Aplysia is known to emit a purple liquid from its body when it receives strong stimulation, such as being attacked by an enemy. It is said that the name Aplysia was given because the way this liquid spreads in seawater looks like rain clouds. 

Aplysia purple liquid

This special Aplysia aquarium has a mechanism in which water drops drip from the top, making it look like it's raining, and you can observe Aplysia.

In addition to Aplysia, which you will never get tired of watching as they slowly eat seaweed at their own pace, there will also be a special aquarium for animals such as the Japanese tree frog and the Tokyo Dalmatian frog, which can be found in Ibaraki Prefecture. Enjoy a day unique to the rainy season at Aqua World Oarai with rain-related creatures.

Japanese tree frog
tokyo daruma frog
Exhibition periodSaturday, May 2024, 6 - Sunday, June 15, 7
Exhibited creaturesAplysia, frogs
Venue3rd floor Shark Daddy's Room
*The creatures on display may change depending on the situation of the creatures.

They look just like Aplysia eggs! ? Amazing sweets

Aplysia egg mass

The rainy season is the breeding season for Aplysia, where they appear on rocky shores with thick seaweed and lay yellow egg masses with multiple eggs tied together in the shape of strings. It is called a ``sea elephant'' because of its shape, and for a limited time, the hotel's relaxing cafe ``Mermaid'' will sell a menu that resembles an Aplysia egg mass as a Mont Blanc.

Aplysia eggs! ? Mont Blanc

The whipped custard Mont Blanc is inspired by a yellow egg mass, and is served with a sweet and sour blueberry sauce that resembles the color of Aplysia's body fluids, further enhancing the ``Aplysia egg flavor''.

Enjoy discoveries and surprising sweets that will deepen your knowledge of living things.

PriceAplysia eggs! ? Montblanc with postcard
680 yen (tax included) *Limited quantity
Sales location3rd floor relaxing cafe “Mermaid”