As part of our Aqua Adventure ticket we pre purchased the combo ticket that allowed us into the lost chambers aquarium. We chose to do this after we had finished in the park at around 5pm. The aquarium isn't big and will only take you about 30mins to walk around. Located opposite Aquaadventure it is a nicely themed aquarium with some fish I had not seen before.
By the larger tanks there were cushions on the floor that you could sit on, relax and enjoy watching the fish. My Octonauts fans were very excited by it all. The whole area was well themed.
Even though we visited the Aquarium at 5.30pm as Aquaadventure was emptying out, it was not busy. It is not a large Aquarium and you can walk round it easily in 15 minutes. There is a small area where you can touch some star fish.
I particularly liked the eels and the large tanks.
If we were to visit Aquaadventure again, I wouldn't go to the lost chambers as I feel we have already done it, but I did enjoy it and think it made a lovely end to our day.