As I have a Merlin Annual pass whenever I am in London I try to visit one of their attractions if I have some spare time.
The Sea Life London Aquarium has a number of different habitats over a number of floors. The main one being the shark exhibit in a tank with Easter Island Moai (I always have a fondness for moai since my trip to Easter Island in 2010).
I do think the Aquarium is a bit small though as you can walk around it in about 30 minutes so would not be happy if I was paying full price.
The location is great on the South Bank next to the London eye, London dungeon and Shrek’s adventure.
I got there by walking over the bridge from Embankment station.