Different colours of Iguana come from different places. If I remember red Iguanas actually come from Cuba, blue Iguanas south east South America, green Iguanas from eCntral america and there is some other colour in between, possibly a shade of green, but they are all the same species. As for dogs, the difference between different breeds of dog is less than 1%, the definition of a species is its members can breed and create viable and fertile offspring. If they can do that then technically they are the same species. The differences between dogs are due to selective breeding but they are all the same species. Possibly one day the selective breeding will cause different breeds to become different species but as they can still interbreed with wolves it is a long way off. Dogs and wolves are the same species, dogs just have the traits we want because we selectively bred those traits into wolves.
i have a red iguana to, and it seems to me that red iguanas are calmer than green iguanas from what i heard from various people.