The key difference between multiple fission and fragmentation is that multiple fission is a type of fission in which the parent nucleus divides several times mitotically, producing several new daughter cells, while fragmentation is a type of asexual reproduction in which the parent organism just breaks into several fragments which are capable of growing into new individuals.
There are two types of reproduction as asexual reproduction and sexual reproduction. Asexual reproduction occurs from a single parent. It does not involve male or female gametes. Moreover, there are different types of asexual reproduction methods. Some of these include fission (binary fission and multiple fission), fragmentation, regeneration, budding, spore formation. However, this article mainly focuses on the difference between multiple fission and fragmentation.