Parasitism is an interaction between two species in which one (the parasite) benefits while the other (the host) is harmed.

An example of parasitism is between Pearl fish and Sea Cucumber. The Pearl fish live in the Sea Cucumber's cloaca which they enter through the anus. The Pearl fish then breaks through the respiratory membrane and situates its home.

The Pearl fish feed on the Sea Cucumbers respiratory tissues and gonads. They also leave their nest at night to feed.

When Pearl fish leaves the cucumber to feed, they follow a chemical scent that leads them back to the cucumber's anus.

The Sea Cucumber can reproduce within the pearlfish. The Pearl Fish live within the host as a child and as an adult the Pearl fish only lives in the Sea Cucumber when it wants to conceal itself from predators. This symbiotic relationship is another example of commensalism.

This is a project that Kai and Ashley made for one of the marine biology classes. They made this clay model of Sea Cucumber and Pearl fish and presented it to the class.

This is the actual poster that Kai and Ashley presented. It explained about the symbiosis relationship between the Pearl fish and the Sea Cucumber.