Water fleas are found in freshwater environments but a few are also found in the marine environments. Water flea are filter feeders. They eat the algae, bacteria and other small protozoa that grow in the water body. Since the diet of Water flea depend on the algae, a reduction in the numbers of algae will affect the food supply of the Water flea. This will affect the Water flea's carrying capacity leading to a decrease in their population size.