Asexual reproduction: when one individual anemone divides to produce two identical but smaller twins. When the anemone breaks off forming another anemone. This is what we call budding. This form of reproduction involving a single parent. The offsprings only inherit the genes of that single parent. It does not require mating or fertilization.
In shallow water sea anemones are smaller and less common, the anemones typically reproduce asexually. But those in deep water tend to be larger and more common the anemone will reproduce sexually.