sera Micron Nature Fry FoodPowdered fry food with zooplankton (18% krill) and phytoplankton (51% spirulina) sera Micron Nature is the fry food without dyes and preservatives for the healthy nutrition of fish and amphibian fry as well as Artemia nauplii in fresh and marine water. This finely powdered food contains both zooplankton (18% krill) and phytoplankton (51% spirulina), and consists of tiny particles that float in the water. sera Micron Nature thus optimally resembles