No, it's an autotrophic Chlamydomonas, which is a kind of algae. It's just a single-celled plant with chloroplasts. Its cell wall is mainly composed of cellulose, and it's also a plant. Ceratophyllum is autotrophic. I remember that there was a photosynthesis experiment in the high school textbook. Ceratophyllum was used in the experiment, so it was autotrophic.