Baltic Macoma

The shells are smooth, relatively flat, oval or somewhat trigonal in shape, and less than 30 mm (1.2 in) long. The shell color is polymorphic, varying between individuals and between localities. Often most specimens are white, sometimes most are pink, and also yellow and orange shells may occur. Color is best visible in worn-out dead shells and inside the shell. Concentric growth rings indicating the age of the specimen are often clearly visible.

Limecola balthica is an infaunal bivalve, living buried in the mud or silt, and extending its two narrow siphons to the bottom surface. Through the siphons, it feeds on organic matter on the sediment surface or in the water. Limecola balthica is a euryhaline species, capable of living in a wide range of water salinity, down to 3-4 permille, i.e. 10% of ocean salinity. It usually lives in the intertidal or shallow subtidal, and is common in estuaries and bays. In the brackish Baltic Sea it lives submerged down to water depths over 100m.