Yes it's just one long reef tank, touted as 'Europe's longest saltwater aquarium tank'. The entire aquarium is made up of only the four tanks you can see here. It's all in the space underneath the concert hall in Tivoli gardens, so this hallway is also a passage to move from one side of the concert hall to the other.
@devilfish Is this aquarium the only animal exhibit at Tivoli Gardens, or are there other reasons for zoo nerds to visit this park?