# Hydra as an algae eater?



## Faruk Gençöz (Nov 4, 2005)

I have noticed hundreds of little green hydras in one of my nano tanks. I could not understand how could hundreds of them survive in a nano tank in which there was no aquatic bug, no fish and no fish food. After reading about them I realized that they can eat algae (chlorella). Actually they don't exactly eat chlorella but there seems to be a symbiotic relationship between them inside the hydra's body. Hydra produces CO2 for the algae and the algae produces food for the hydra. The green color of hydra comes from chlorella inside the hydra's body. It was interesting to learn that they vacuum microscopic algae.


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