It may be colorless, brown, reddish or bluish in color, depending on the local environment.

Unlike other crustaceans, amphipods lack carapaces and have laterally compressed bodies.

Gammarus lacustris plays an important role in many of the freshwater ecosystems that it inhabits.

This influences its biology: at low altitudes, it is known to die after first reproduction, but in colder waters, it lives to reproduce repeatedly.

[4] As a small aquatic invertebrate G. lacustris is an important food source for many organisms.

[10] Gammarus lacustris has been noted in northwestern Europe, Russia, and North America.