like yoink said, they are not native, but an invasive species. someone imported them years ago as feeders or some similar purpose and once loose they found Hawaii perfect like most other invasive species, no competition or real predators. they have been sold by the lfs here as feeders for decades, i have bought them since i was in elementary school. also, the ones in our streams are not RCS, but the wild form. the red and all other colors are illegal here.