In two years after biomanipulation of Lake Zwemlust (The Netherlands), macrophytes (helophytes, elodeids) and filamentous algae developed luxuriantly in the lake. They influenced the structure of macroinvertebrate communities inhabiting them. Macrophytes and algae, by changing environmental and trophic conditions, also affected the composition of macrozoobenthos. Vascular plants served as an important source of food for zoobenthos and phytofauna, mainly after they were decomposed. Filamentous algae were consumed readily alive by many animals. Invertebrates appeared to be important as a potential nutrient source for hydrophytes.