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Some cardinalfishes are small and careful enough
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to hide amongst the spines of the crown of thorns starfish or the sea urchin,
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thereby using the defense of the host to protect themselves.
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This is known as a "commensal" relationship,
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whereby one partner in the relationship benefits
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while the other receives neither benefit nor harm.
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It's a similar strategy adopted by anemonefishes.
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They make their home in sea anemones,
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the perfect refuge from predators.
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Their skin has a special immunity from the anemone's stinging tentacles.
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Skunk clownfish tend to favor the magnificent sea anemone.
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Clark's anemonefish are not so particular
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and find their home amongst a number of species of sea anemone.
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This is a mutually-beneficial relationship.
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While the fish are protected,
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their feces provide food for the anemone
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and they help keep it free of parasites.
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They also chase away polyp eaters such as butterflyfishes,
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thereby defending the anemone as well as their own family.
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Some even attempt to chase off passing divers.
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Juvenile Clark's anemonefish are predominantly orange in color.
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Saddle anemonefish are not so prevalent
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and are commonly associated with bubble-tip anemones
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such as here at Richelieu Rock.
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Juveniles display a white stripe reminiscent of other adult species.
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Anyone who has seen the film "Finding Nemo"
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will already be familiar with ocellaris clownfish.
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They are normally found living amongst magnificent sea anemones.
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Typically an anemone hosts a dominant female matriarch and her male mate,
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as well as one or more juvenile anemonefish.
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When the female dies, the male transforms into a female
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and the highest ranking adolescent is promoted to be her mate.
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Due to abnormally warm sea conditions,
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this anemone has lost the symbiotic zooxanthellae that give it its color,
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and may or may not recover.
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Other types of fish have also evolved a resistance to the sea anemone's sting.
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Juvenile domino damsels are often seen around sea anemones.
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Competition with anemonefishes, as well as with each other,
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can be fierce and incessant.
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As adults they are one of the most aggressive fish on the reef, for their size,
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and become less reliant on anemones for protection.
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Another creature that uses the anemone to protect itself
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is the porcelain anemone crab.
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At the end of the crab's third maxillipeds
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is a fan of bristles known as "setae"
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which the crab holds against the current to filter plankton from the water.
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Any collected food is scraped into the mouth
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by smaller setae on the innermost maxillipeds.
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Tube anemones are often seen in isolation on the seabed.
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This tube anemone's stinging tentacles provide protection for a magnifcent shrimp,
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as well phoronid worms which cover the tube.
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A pair of whitecheek monocle bream pass by.
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Jellyfishes, of course, are well known for their sting
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and often attract hitchhikers such as small sardines.
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The small fishes remain in the vicinity of the jellyfish,
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sometimes for their whole lives.
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When attacked, they find protection under the jellyfish's bell
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or even right inside, past its stinging tentacles.
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These hitchhikers are sheltering in a crowned jellyfish.
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And this rhizostome jellyfish is harboring juvenile scad.
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Older scad change from hunted to hunter.
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The jellyfish's sting is no guarantee of its own survival.
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This Australian spotted jellyfish at Racha Yai
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comes under attack from a scrawled filefish.
