I visited aquamarine park while staying in Iwaki. It was a wonderful experience. It's a very educational aquarium where they try to educate guests on many different topics. You learn a lot about nature of Fukushima, but also deep sea animals, whaling in japan and our interactions with the ocean.
They have many animal species that I've never seen in real life before. Most of their animals seem to have a lot of space and their exhibits have been catered to their habitats and needs.
I think it is one of the better aquariums I have been to.
Amazing experience at the aquarium today. The animals were upclose and you can see the tuna and sardines swimming in a school in the tank. There are other outdoor areas that are kids friendly too! Must go if you are in iwaki