Heteroscarus acroptilus, the rainbow cale, is a species of weed whiting endemic to Australia where it is found in marine waters along the southern coast.[1] It inhabits rocky reefs that have plentiful growth of brown algae and also in beds of seagrass, particularly those of the genus Posidonia.[2] It occurs at depths of from 1mto15mm (03feetto49feetm). This species grows to a length of 24cm (09inches) SL. It can also be found in the aquarium trade. This species is the only known member of its genus.