Your partially right. They can clone themselves to help preserve the specie, but they will breed with others of their same specie, thus how you get color morphs. Btw hermaphrodites just have both sets of breeding organs but still need a partner to breed with, the term you were thinking of was asexual. If something is asexual it can reproduce regardless of having a breeding partner or not. Allot of snails actually tend to be semi-asexual meaning that they will clone themselves if there is no partner to breed with but if there is they will choose to breed with a partner to help diversify the Gene pool. Also just because something clones itself doesn't mean that mutations won't appear even if the original has no outward mutation to speak of.