Herring live in enormous schools, sometimes containing millions of fish. They swim at deep depths during the day. In the evening, they follow their prey closer to the surface and disperse just under the water surface for the night. Herring feed on small crustaceans, free-swimming snails and fish larvae. As they swim, they sift these small animals out of the water with the help of filters located on the inside of their gills. The filter is made up of long 'thorns' which are situated as a comb on the gills. In the Netherlands, herring is particularly known as the 'Holland Nieuwe'. All the various herring sold at the fish shop, the new herring, pickled herring, rolmops, salted herring, bokking and pan herring, are all the same fish.