Being primary producers, diatoms are consumed by lots of organisms. In order to ward off the diversity of feeding strategies and to fight for their existence, diatoms have developed extreme stable exoskeletons strengthened by silicate in a multitude of different forms. Diatoms live in different habitats. Some are planktonic, living in the upper water layers, some live attached to stone or seaweeds and others live in the sediments of the benthic division and are able to move actively through it. Because they occupy different habitats, there is a variety of predators. Planktonic diatoms are mainly ingested by planktonic copepods, while diatoms which live in sediments are ingested by nematodes and some gastropods rasp on epiphytic or epilithic diatoms. Hence it can be supposed that diatom-species living in different ecological niches have developed different kinds of stability. In this study, feeding strategies and tools of different predators were examined. The aim has been to test whether diatom-armour is more stable against the feeding tools of predators living in the same habitat, and whether diatom-armour is less stable, if the predator does not live the same water-layer. Feeding-strategies and feeding-tools of different copepods, gastropods and nematodes have been examined by means of scientific literature and additionally by dissecting a radula of Littorina littorea and analyzing its structure and organization by confocal microscopy. N. Niebuhr has performed virtual crashtests between models of feeding-tools of the predators and diatom-models, based on the collected information about feeding-strategies and properties of the feeding-tools. The crashtests showed that the planktonic diatom-species Asterolampra spec. owns best resistance against feeding-tools and -manners of copepods, while it resists poorly against feeding-manners of nematodes and gastropods. Actinoptychus spec., living in sediments, was very instable against the feeding-manners of copepods and more stable against nematodes and gastropods. The last thing to point out is that Arachnoidiscus spec., an epiphytic diatom, showed almost the biggest strength against all kinds of feeding-manners.