Euglena is a genus of unicellular, freshwater organisms that are very common in ponds and small bodies of water, especially if they are rich in nutrients and consequently high in algae (aka 'pond scum...Euglena is a genus of unicellular, freshwater organisms that are very common in ponds and small bodies of water, especially if they are rich in nutrients and consequently high in algae (aka 'pond scum' ). Euglena itself is sometimes photosynthetic and is a component of the green sludge in such ponds. But at other times it is non-photosynthetic and is a component of the diverse group of organisms that are eating the green sludge or perhaps eating the other things that eat the green sludge.
