These pint-size beauties are fierce defenders of their turf. Check out these 9 interesting facts about the clownfish, or anemonefish.

• All anemonefish begin life as males, and live in small family groups inside the tentacles of anemones. The largest is a sex-changed female, the next in size is the breeding male, and the remaining two or three smaller members are nonbreeding males.

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• Poor swimmers, anemonefish cannot survive without inhabiting the stinging tentacles of anemones.

• There are more than 1,000 species of anemones worldwide, but only 10 species host anemonefish.

• The 29 known species of anemonefish, all from the Indo-Pacific, are members of the damselfish family.

• A species of isopod attaches to the tongue of a few anemonefish, which causes the organ to waste away. The tongue is permanently replaced by the isopod, which — believe it or not — causes no permanent harm to the fish.

• Anemones, members of phylum cnidaria, which includes stony corals and jellyfish, all have the unique ability to sting both predators and prey.

• The beautiful Banggai cardinalfish from Indonesia has adapted to share anemones with anenomefish.

• Popular with home aquarists, a few species of anemonefish are now bred in captivity for the aquarium trade.