Palaemon adspersus is a caridean shrimp characteristic of brackish water. It has a distinct, well-developed rostrum, with 5-7 dorsal teeth (one dorsal tooth lying posteriorly to the orbit), and usually three (sometimes two or four) ventral teeth. The rostrum has a weak ventral expansion. The carapace bears antennal and branchiostegal spines.

Palaemon adspersus is uncommon over most of north-western Europe, but forms the basis of a significant fishery in the Danish straits. In the Baltic Sea, it can tolerate salinities as low as 5 ‰, but it overwinters in deeper, more saline waters offshore.