What do diatoms eat?
Diatoms are in kingdom protista. They are also in the plantlike protist category so therefore they are eukaryotic, single or many celled, and have chloroplasts which contain chlorophyll. The chlorophyll causes them to use energy from the sun to make food that they eat.
Diatoms are also filter-feeders. As they move through water, they filter particles through their two silica shells as means of processing food.
I recently studied different types of protists, and Diatoms, being plant-like protists, are a separate category from Euglanoids. I learned that Euglanoids are the only plant-like protists which can, on occasion, be heterotrophs (predators, not plants). This would mean that yes Diatoms can eat other organisms.