At an aquarium in Oita Prefecture, a rare blue crab is currently on display and is being billed as a "blue crab of happiness."
The swimming crab, also called a Japanese blue crab, is usually a yellowish brown, but the one shown at Umitamago aquarium in the city of Oita is clear blue.
According to the aquarium, the crab was caught in July off the coast of Kunisaki Peninsula in Oita. It is a male crab with a 15-cm-wide shell weighing about 380 grams.
The aquarium officials believe the crab turned blue because the amount of pigment contained in its shell differs from that of other crabs.
"I hope people will come to see it before it's too late, because it might turn to a different color once it sheds its (shell)," one of the officials said.