Based on the article, which is true about clownfish?

They produce a toxin that protects them and nearby anemones.
They use anemone toxin as a protective coating against predators.
They eat anemones because they are immune to anemone toxin.
They live inside anemones because they are immune to anemone toxin.

They produce a mucus that makes them immune to the anemone's toxic sting.