Releasing exotic fish into waterways upsets natural ecosystems, by forcing native species to compete for habitat, degrading water quality, introducing parasites and disease, and depleting native insects, fish eggs and plants. They can breed quickly, making it difficult to get rid of them.

Pet birds can upset the delicate ecosystem when released into the wild. They can impact native species by introducing diseases and taking away food resources and places to nest. It is estimated there are on average 491 pet birds on the loose in Auckland in any given month.

Turtles in the wild will eat a wide variety of aquatic plants as well as fish, baby birds, insects, lizards and frogs. 

Escaped exotic lizards are becoming increasingly common. Some species could readily establish invasive populations, posing a risk to indigenous species: spreading diseases, eating insects, and competing with native lizards.

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Image: Nick Ling