Members of the public were able to share in a special moment with Rainbow Springs.
Rainbow Springs welcomed 200 giant kokopu (galaxias argenteus) to the park last Thursday, with visiting children invited to help transfer the fish into the pool.
Giant kokopu are the largest adult fish of New Zealand's whitebait species, endemic to New Zealand and classified as endangered.
Rainbow Springs' business manager David Hennigan says projects like this are vital for the future of New Zealand's endangered species.
"We saw it as another opportunity to do what we can for the native species of New Zealand.
"This country has lost so much already and too many species found nowhere else in the world are still in danger of extinction."
The giant kokopu were donated to Rainbow Springs as part of New Zealand Premium Whitebait (NZPW) 'Fish Ark' project.
NZPW reproduces, hatches and grows whitebait in its Warkworth fish hatchery - the only native whitebait fish hatchery of its kind in New Zealand.
Rainbow Springs' wildlife programme manager Mark Paterson says while there were 200 being released that day, they will end up with 2000 giant kokopu at the park.
He says having the kokopu is pretty special from a conservation perspective.
Rainbow Springs' broodstock manager Katie Pepper says it is quite rare to see really big kokopu in the wild.
"People don't even realise when they come to us and see these fish that they start off as whitebait."
New Zealand Premium Whitebait chief executive Jeremy Gardiner says these are beautiful, lovely fish to deal with, and it's great to be able to promote the species.
Keira Manley-Frost, 5, says she liked being able to help release the giant kokopu into the pool.
She says they were funny, and had been splashing around and wet her.