E. exiguus favours shores with moderate wave exposure or shelter, including estuaries, and salinity down to 6‰ in the outer Baltic
The high turbidity of the Mersey Estuary, England, inhibits algal growth other than near high water mark where submersion is shallow and of short duration, but the hydroid Obelia dichotoma grows at lower levels on scattered rubble and human debris amid the muddy sand. E. exiguus feeds on the hydroid.
Wirral coast of Mersey Estuary, England, October 2010.