 Zooplankton feed on bacterioplankton, phytoplankton, other zooplankton (sometimes cannibalistically), detritus (or marine snow) and even nektonic organisms.As a result, zooplankton are primarily found in surface waters where food resources (phytoplankton or other zooplankton) are abundant.Just as any species can be limited within a geographical region, so are zooplankton.