Pond Ecosystem Tier 4- Larval Insects
Larval insects consume rotting organic matter and zooplankton. This level of the eco-system is important because these insects are food for higher levels, such as frogs and fish.
Worms and leeches cannot harm anything, other than the tadpoles, snails, worms, and other small animals living in the pond which they can feast on. However, blood is not the only food of leeches. They also help the pond by eating decomposed organic material, and sludge from the bottom of the pond and the filter.