What primary consumers eat phytoplankton?

Primary consumers that eat phytoplankton are typically small aquatic organisms known as zooplankton. This group includes tiny crustaceans such as copepods and krill, as well as larval stages of various fish and invertebrates. These consumers play a crucial role in the aquatic food web, as they convert the energy stored in phytoplankton into a form that can be utilized by higher trophic levels, such as fish and larger marine animals.