Marine scientist advises parents to leave 'Dory' on the big screen

The palette surgeonfish, or blue tang, is the star of Disney-Pixar's latest film Finding Dory—the much anticipated sequel to the 2003 blockbuster Finding Nemo.

With the release of Nemo, anemonefish became the pet of choice and the demand for the bright orange, black and white saltwater fish rose drastically, causing the wild population of clownfish to shrink. Scientists fear the blue tang will suffer a similar fate once Finding Dory hits theaters.

"My understanding is that palette surgeonfish are difficult to breed in captivity, which means many of the fish in shops will be collected from the wild," said Assistant Professor of Biological Sciences at Florida International University Alastair Harborne. "This obviously decreases their populations and may damage the reef as collectors use nets to catch the fish."

The blue tang is a saltwater fish living in coastal waters, coral reefs and inshore rocky or grassy areas anywhere from 6 feet to just over 130 feet deep. The potential of its decreased population is cause for concern not just for the fish but also for its habitat. The blue tang feeds on algae which helps keep corals healthy. Without grazers like surgeonfish, reefs can become overgrown with algae causing corals to suffocate.

As a reef fish ecologist, Harborne shares these concerns. He provides some insight about blue tangs and why they do not make good pets while offering alternatives for parents who may be thinking about finding Dory for their kids:

• Watch out for that scalpel! The blue tang is part of the surgeonfish family – and they are called surgeonfish because they have scalpel-sharp, venomous spines at the base of their tails. In the wild, they use these spines for defense and in captivity they obviously pose a risk to people handling them – this means they are not an ideal pet, especially for children.
• Surgeonfish are bigger than anemonefish. The blue tang averages 12 inches in length so they need a bigger tank. While anemonefish are site-attached, meaning they live on a single anemone, surgeonfish tend to roam around the reef needing a bigger tank to remain healthy.
• Keeping saltwater fish is expensive. Keeping a saltwater tank – as necessary for a reef fish like the palette surgeonfish – is not cheap or easy and requires a significant amount of investment and expertise to ensure water quality is maintained. It is much easier to keep a freshwater tank where water can be used straight from the faucet after adding some treatment drops to dechlorinate it. Also, while freshwater fish cost a few dollars each, saltwater fish like the blue tang can cost upwards of $50 or more.
• For beginners, freshwater is the way to go. If you haven't kept fish before, start with a freshwater tank and get some hardy, cheap freshwater fish to build up your expertise and to ensure you want to keep fish beyond the short-term excitement of seeing the film. You can get a nice affordable starter kit for a freshwater tank from most pet stores. Enjoy your freshwater tank and then go snorkeling or diving to see reef fish!

Although Finding Dory should not be the reason to rush out and get a blue tang, the movie provides a great teaching tool for parents and educators alike. The film can spark conversations about aquariums, ocean ecosystems, caring for ocean animals, careers in the marine sciences and more.

Harborne is an ecologist primarily interested in coral reef fishes, with a particular focus on the impacts of environmental change on these fishes and aiding their conservation. Much of his current work, in the Caribbean and Pacific, is examining the natural processes and anthropogenic impacts that control the abundance, ecology and behavior of reef fishes and integrating this work into food web models to provide a comprehensive understanding of tropical communities and the threats to their health.

Finding Dory swims into theaters June 17.