A zoochlorella is a small, granulelike body found in the interior of some stentors, hydras, and other invertebrates.
according to my research zoochlorella is an green algae.
A lot of sea anemones have a facultative ectosymbiotic relationship with zooxanthellae and/or zoochlorella. Obviously these need light to carry out photosynthesis, and so in that sense yes, they do need light. However it is not really the anemone that needs the light, it's the algae and the anemone can survive without the algae, so in that sense no, they don't need light. It depends on what you meant by the question.
Algae mostly inhabit marine water, but can also be found in fresh water rivers(eg: Batrachospermum), standing water(eg: Ulothrix), and hot water(eg: Chlorella). Algae also inhabit terrestrial habitats like moist soil and walls, bark of trees, polar regions( eg: Haematococcus nivalis which develops red snow in polar regions), etc. They also occur inside plants and animals, like Zoochlorella and Zooxanthellae which occur inside the body of Hydra(symbiotic relationship).