These fish have been near the Fukushima Reactor disaster and are not normal, but some with mutations, such as having more eyes than a normal fish. But despite it makes them looking a bit odd, they have better vision than normal fish and are certainly one of their kind and the radiation is not contagious and will have no effect on you. They are nice fish and come in different sizes. They like humans and they would love to be given a new home. Just grab one, while stocks lasts or buy one as a gift for your loved one.