Dozens of different species of tintinnid ciliates (hairy things in the tiny shells), all of them grazers on microscopic algae

So many different species, doing pretty much the same jobs, should not fit together so nicely. How do all these different species co-exist? The 'Paradox of the Plankton' is that so many apparently similar species do co-exist. These tintinnids species are packed in a way that allows stable co-existence- the question is how are they packed?