Caridina serratirostris

Caridina serratirostris is a species of freshwater shrimp that lives in the Indo-west Pacific region, from Madagascar to Fiji, including northern Queensland. 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).