Some invertebrates are parasites that live in or on other animals and derive nourishment from their host species. Some invertebrates live symbiotically with other organisms. Another example is the association between sea anemones and clownfishes. The clownfishes gain protection while the sea anemones get bits of dropped food. The broadcast method is another method of sexual reproduction used by invertebrates where both male and female gametes are released into the water in enormous quantities and left to unite by chance.
Many invertebrates are hermaphroditic, possessing both male and female sex organs.
Despite this they usually lack the capability to self-fertilize and reproduce in a more typical sexual fashion, with both partners bearing young. Others reproduce asexually. Asexual reproduction results in a genetically identical copy of the parent and is characteristic of cnidarians such as corals and hydroids, and certain worms and sea squirts. Some invertebrate species change sex at different periods in their lives. For example, some shrimp species start life as males and later become females.