Identify the organism that is being neither harmed or helped in Finding Nemo ​

Some have lifelong relationships with other organisms, called symbiotic relationships. There are three different types of symbiotic relationships: mutualism, commensalism, and parasitism. Commensalism: only one species benefits while the other is neither helped nor harmed

a. decomposes use carbon from dead organisms as fuel for cellular respiration, returning carbon dioxide back into the atmosphere.