The Gouldian finch (Chloebia gouldiae), also known as the Lady Gouldian finch, Gould's finch or the rainbow finch, is a colourful passerine bird that is native to Australia.
Both sexes are brightly coloured with black, green, yellow, and red markings. The females tend to be less brightly coloured. One major difference between the sexes is that the male's chest is purple, while the female's is a lighter mauve.
Gouldian finches are about 12.5–14 cm long. Gouldian finches' heads may be red, black, or yellow. Formerly considered three different kinds of finches, it is now known that these are colour variants that exist in the wild. Selective breeding has also developed mutations (blue, yellow and silver instead of a green back) in both body and breast colour.
There are several "prominent rounded tubercles" with an "opalescent lustre" at the back of the gape. These tubercles are commonly (and incorrectly) described as phosphorescent in spite of much scientific evidence to the contrary. It is believed that these tubercles simply reflect light and are not luminescent.