The English name "Codfish Island" refers to the endemic blue cod, which is fished commercially in surrounding waters by trapping in baited pots.

The Māori name "Whenua Hou" means "new land", which dates back to the early days of Pākehā settlement in New Zealand.

[4] Codfish Island / Whenua Hou is home to southern short-tailed bats, kākā, fernbirds, red-fronted and yellow-crowned parakeet (both referred to as kākāriki), Pacific black ducks and a recently introduced population of mōhua.

The island has been identified as an Important Bird Area by BirdLife International because of its significance as a breeding site for several species of seabirds, including Fiordland and yellow-eyed penguins, and mottled, Cook's and Whenua Hou diving petrels.

[5] The first kākāpō were transferred to Codfish Island / Whenua Hou in 1987 from Rakiura in order to provide a safe haven for the birds.