Species within the genus, Acanthamoeba, are generally free-living trophozoites. These trophozoites are relatively ubiquitous and can live in, but are not restricted to, tap water, freshwater lakes, rivers and soil.[18] In addition to the trophozoite stage, the organism can also form a double-walled cyst which may also be present in the environment, and can be very difficult to eradicate through medical treatment. Both of these stages are usually unnucleated and reproduce by the means of binary fission.[19]