 The aquarium acquired piranhas from Cleveland, Ohio, U.S., in 1979, trading seahorses for them.In 2019 the 21 elderly piranhas remaining were euthanased, as new government rules no longer allowed them to be kept in the aquarium's tanks.In 2002 the aquarium underwent a NZ$8 million extension and renovation which included the addition of a 1.5 million litre oceanarium with a 50m acrylic tunnel and the replacement of all the original tanks with newly constructed ones.