Caridina serratirostris is a species of freshwater shrimp that lives in the Indo-west Pacific region, from Madagascar to Fiji, including northern Queensland, Australia, which may be a different subspecies. Its common name in the aquarium trade, "ninja shrimp", comes from its ability to quickly change colour and disappear into its surroundings like a ninja. Adults grow to a length of 25–35 millimetres (1.0–1.4 in).