Kelly Tarlton's Underwater World is 25 years old. For today only they have $5 entry. (News shared by @ViewAuckland on Twitter.) As part of the celebration they also have competitions and online kids activities.
The aquarium has come a long way from it's beginnings as sewerage holding tanks under the Auckland waterfront. Construction on the tunnels started in 1984 using an innovative technique to mold plastic sheets to the correct curve and dimension. The Underwater World opened in 1985. It was an immediate success. Tragically Mr Tarlton died only a few weeks after the opening. The staff have continued to develop the aquarium, opening the Antarctic Encounter in 1995.
There are three different experiences that visitors can go on. Antarctic Encounter, Underwater World and Animal Adventures. (I don't know if the reduced entry fee applies to all experiences.)
The website has a short biography of Mr Tarlton.
Throw me the wreck, Johnny : memories of Kelly Tarlton, the man behind the legend by Steve Locker-Lampson. (1996)
"The interviews ... for this book took place between March 1995 and March 1996 ... the majority of his friends and colleagues remain hale in both limb and memory"-- p. 9."
Kelly : the adventurous life of Kelly Tarlton by E.V. Sale. (1988)