Euglena gracilis reproduce through a process called mitosis. In order to complete this process, they must be exposed to the right temperature and must be well-fed. Once a Euglena gracilis completes mitosis, it will split its self in two, which results in another Euglena gracilis. The completion of this process is best observed when another eyespot appears on a Euglena gracilis that is splitting in two.
The Euglena gracilis primarily consumes algae and depends on having sufficient light in order to create their own food. If they lack enough light to create their own food, they will swim around and search for tiny organisms to eat, such as paramecium and amoeba. Euglena gracilis are tiny organisms that belong to the Protist Kingdom and are commonly found in marshes and ponds.