You might have heard of the ‘Nemo effect’, which described the increase in sales of clownfish (Amphiprion percula) after the release of the movie ‘Finding Nemo’. Although many news outlets reported on this phenomenon back in 2016, there is actually little evidence that it was real. 

One 2017 study did show that there was no increase in sales of clownfish after the movie came out, but it was based on limited data. That is why a recent follow-up study by zoologists at the University of Oxford, U.K., looked at the impact of the sequel ‘Finding Dory’ not just on the sale of blue tangs (Paracanthurus hepatus) like Dory herself, but also the public’s general interest in the fish. Because blue tangs can't be bred in captivity, the researchers were safe to assume all the extra fish that would be sold would have to be fished out of their natural habitat. Luckily, the researchers found no increase in sales of the fish. This puts the idea of the 'Nemo effect' to rest.

They did find evidence that more people looked up information about blue tangs in the first two months after the movie was released, suggesting that the movie had a positive effect on conservation awareness. Movies containing wildlife do have an effect on society, it just might not have been what we always thought  — and for tropical fish, that's a good thing.