Blagdon Pond Oxygenator Pumps add essential aeration for good pond water conditions and healthy fish. Good aeration stops pond water stagnation prevents fish dying from lack of oxygen helps sick fish recover improves waste breakdown and aids filtration. Koi Air pumps are specifically designed for use in larger ponds where the ability to pump to several metres depth with a number of airstones is important. With a robust rubber diaphragm this koi aeration system is durable and easy to replace when needed. Specifically designed for larger ponds it has the ability to pump to a depth of several metres and encourages pond and fish health as aeration is essential for a healthy pond.