Oxygen is less obviously needed in the aquarium, but still in sufficient quantities. Fish reabsorb the oxygen bound in the aquarium water through gill respiration and, similar to most mammals, CO2 is exhaled again. For some sensitive aquarium inhabitants, a strong fluctuation of the oxygen supply can have dramatic consequences. It is therefore advisable in some cases to prevent a low oxygen concentration. This can occur when there are particularly many fish in the aquarium, a spontaneous algae bloom appears or the filter gradually loses part of its circulation capacity due to contamination. Fish and shrimp then swim to the water surface and gasp desperately for air. For this purpose, Tetra has the right accessories. They designed the powerful APS aquarium air pumps and the small Air Silent pumps. The compressed air produced is broken down into fine bubbles via an air outlet and dispersed in the water column. By placing them in the direction of the flow, the air bubbles are distributed throughout the aquarium.