Visitors can enjoy a panoramic view of jellyfish in a 14-meter-wide tank at the Sunshine Aquarium in Tokyo from Thursday.
The new tank seems to rise from the floor from a darkened area where moon jellyfish glow.
"I hope people can be relaxed by feeling like they are floating in the deep sea with the jellyfish," an aquarium official said.
The aquarium's jellyfish section includes six types of tanks, including one with a tunnel through which visitors can walk.
Tickets must be bought in advance for a specified date and time, with prices at 1,200 yen ($11) for a child and 2,400 yen for an adult.
Sunshine Aquarium, which had been closed for around three months due to the novel coronavirus pandemic, reopened on June 8.