Explanation

Inverted pyramid is found in biomass pyramid of aquatic ecosystem. In this, the number of producers is maximum but their mass is minimum, which gradually rises up in the successive trophic levels. $e.g.,\ Phytoplanktons\ (minimum\ mass)\ \rightarrow \ zooplanktons\ \rightarrow \ small\ fishes\ \rightarrow \ large\ fishes\ \ (maximum\ mass).$