Befriending Nemo

Clownfish captivate moviegoers, scientists – and anemones.

When Andrew Stanton set out to make an animated children's movie set in the ocean and faithful to "the real rules of nature," all he needed was the perfect fish for his main character.

Combing through coffee table books on sea life, his eye landed on a photo of two fish peeking out of an anemone. "It was so arresting," Stanton says. "I had no idea what kind of fish they were, but I couldn't take my eyes off them."

The image of fish in their natural hiding place perfectly captured the oceanic mystery he wanted to convey. "And as an entertainer, the fact that they were called clownfish—it was perfect. There's almost nothing more appealing than these little fish that want to play peekaboo with you."

So a star was born. Finding Nemo, the Pixar movie Stanton wrote and directed, won the 2003 Academy Award for best animated feature and remains one of the highest grossing G-rated films of all time, taking in over $850 million to date. Nemo—a clownfish of the species Amphiprion percula—introduced millions of children around the world to a wondrous tropical ecosystem: the coral reef and its denizens.

Clownfish get their name from the bold colour strokes on their body (from rich purplish browns to bright oranges and reds and yellows), often divided by stark lines of white or black, quite like the face paint on a circus clown. Seeing clownfish darting among the tentacled folds of an anemone is like watching butterflies flitting around a flowering plant in a breeze-blown meadow—mesmerizing.

Twenty-nine species of clownfish live among the reefs from East Africa to French Polynesia and from Japan to eastern Australia, with the greatest concentration of diversity on the north coast of New Guinea in the Bismarck Sea (where with a little luck and a competent guide you can see seven species on one reef).

On a recent diving trip to Fiji, Gerald Allen—a research associate at the Western Australian Museum and the world's clownfish authority—discovered the 29th species, Amphiprion barberi. That brought his lifetime total to seven clownfish (and nearly 500 species of reef fish). "I still get a huge buzz when I find something new," Allen says. "Amphiprion barberi is a beautiful clown, orange and red like a blazing ember on the reef."

Among scientists and aquarists, clownfish are also known as anemonefish because they can't survive without a host anemone, whose stinging tentacles protect them and their developing eggs from intruders. Of the roughly thousand species of anemones, only ten host clownfish.

It's still a mystery exactly how a clownfish avoids being stung by the anenome, but a layer of mucus—possibly developed by the clownfish after it first touches an anemone's tentacles—may afford protection. "It's a slime that inhibits the anemone from firing off its stinging cells," Allen says. "If you ever watch a new little anemone fish coming into an anemone, it makes these very tentative touches. They have to make contact to get this chemical process going." Thus shielded, the clownfish, in effect, becomes an extension of the anemone—another layer of defense against anemone-eating fish, such as the butterflyfish. What's good for the clownfish is good for the anemone, and vice versa.

Never before has a fish had a bigger boost than the clownfish in the wake of Finding Nemo (unlike the notoriety of a very large mechanical killer with teeth). At first, fear spread through the aquarium industry that the story line would cause a backlash: Nemo is captured and held in a tank in a dentist's office, and his father spends the rest of the time trying to rescue him.

"I'm here to tell you the opposite happened," says Vince Rado of Oceans, Reefs and Aquariums (ORA), a hobby-fish hatchery and wholesaler in Fort Pierce, Florida, whose sales of A. ocellaris—a Nemo look-alike species—jumped by 25 percent. "Thank God for little Nemo!"

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