They are efficient suspension feeders, feeding on smaller zooplankton, fish eggs, and planktonic larvae. This undescribed ctenophore has remarkable coloration. Ctenophores are commonly multi-colored, owing to refraction along meridional rows of fused cilia known as comb rows. The herbivorous copepod Eurytemora affinis is common in estuarine waters all over the northern hemisphere. This is a female, about 1 mm long.
Populations occur in a wide range of salinities.
For example, populations can be found, apparently isolated from each other, in many estuaries in Europe and in North America. Carol E. Lee has been investigating the problem of whether these low salinity populations are one genetically similar group, adapted to low salinity that have dispersed all over the world, or whether the low-salinity populations arose many times independently, perhaps evolving from fully marine ancestors. DNA sequencing evidence thus far supports the independent origin hypothesis. This copepod is a detritivore and also feeds upon phytoplankton. The species is common in Korean, Chinese, and Japanese coastal waters.