Banded Coral Shrimp
Stenopus hispidus
Emperor Shrimp
Zenopontonia rex
About
The emperor shrimp rides through life on the back of someone else, perched on a sea cucumber, nudibranch, or other large host as it slowly moves across the reef. Despite its tiny size, this hitchhiker has been seen tackling prey much bigger than itself.
How to tell it apart
Several tiny shrimp live on the backs of reef animals, but the emperor shrimp is the one almost always riding openly on top of a sea cucumber or nudibranch. Its purple antennal plates confirm the ID once you spot it there.
Appearance
This is a sturdy little shrimp. Its antennae are shaped into flat plates that reach forward from its head, and it has a crest-like point on its rostrum, the pointed structure between its eyes. Its base colour is orange-yellow to orange-red, with purple antennal plates, claws, and walking legs. During the day, patches of white can spread across its back and tail, sometimes covering most of the body or forming a pale band down the middle. Its colour can also shift to match its host, especially when it lives on a nudibranch, a shell-less sea slug.
Habitat
It lives on shallow tropical reefs across the Indo-Pacific, always attached to a host animal rather than free on the seabed. Typical hosts are large sea cucumbers and nudibranchs, and occasionally a starfish, with the shrimp perched on the host's back or side, moving to the far side if something threatens it.
Did you know?
Though it looks like a harmless hitchhiker, the emperor shrimp has been seen hunting: individuals in Bali were recorded attacking and gripping a small shrimp and a young fish far larger than themselves.
Log it in Into the Blue
Describe what you saw and we name it, then keep every species you find in your Oceandex.
