The Amano Shrimp, also known as the Japanese Swamp Shrimp, was chosen for the biosphere because it eats freshwater algae that can be grown inside the biosphere and they live for 2 to 3 years. Amano Shrimp produce waste and tax an aquatic environment just like every other living organism in a tank. So, the small biosphere may support one shrimp for several years. The disadvantage of Amano shrimp is that they cost about $4.00 each and have to be purchased online, minimum five at a time. Pet store do not have them in stock.