In an aquarium two herbivorous species of fish are living together and feeding on phytoplanktons. As per the Gausses principle, one of the species is to be eliminated in due course of time, but both are surviving. How? And what possibly happened to both the species?

Each species has a specific position or functional role within the community, called niche. According to the Gausses principle, no two species can live in the same niche. In this case, two herbivorous species are living in the same niche and feeding on phytoplanktons. It may be because of the availability of sufficient phytoplanktons/and or less number of individuals of the fish species. of the two species might have occured. And though neither of the species have been eliminated, niche overlapping may effect the growth and development of individuals of the species.