-Sea
Anemones and Clownfish
Sea
Anemones are a type of soft coral. They consist of one polyp that is attached
to the reef by an adhesive foot. Their column-shaped body has an oral
disk surrounded by tentacles. These tentacles contain poison that is
used to paralyze prey. Clownfish are immune to the poison and will inhabit
sea anemones. This is possible because clownfish have a slimy mucus
layer based on sugar rather than protein, so that the anemone may not
recognize it as food, and because of the different movements of clownfish
from other fish. 
Clownfish are brightly colored and poor swimmers, so
living in anemones gives them protection. Anemones feed on food scraps
left over by clownfish. Certain species of clownfish are found to inhabit
certain species of sea anemones. An individual clownfish always stays
close to its sea anemone and is never more than 6-12 inches away from
it at any given time.
-Coral
and Zooxanthellae
Corals
are inhabited by a type of algae called zooxanthellae, which are the
source of their bright coloring. The zooxanthellae get their food by
photosynthesis, a process in which light energy is converted to chemical
energy. Coral then receive the products of photosynthesis as part of
their diet, while the zooxanthellae are given a home and access to light.