On coral reefs, “Dory,” the small vibrant blue fish with black stripes and a yellow tail, is known by several other names: Hippo Tang, Royal Blue Tang, Regal Tang, Palette Surgeonfish and by the scientific name Paracanthurus hepatus. They live in warm waters at 2-40 meters deep in the Indo-Pacific Ocean and can grow up to 12 inches (31 cm) long.

Blue Tang are one of more than 70 species of surgeonfish, a group of fish known for the very sharp spines near the tail. They normally hold these spines close to their body, but they can extend them when threatened.

When they are young, they feed exclusively on plankton. As adults they are omnivores, eating both algae and invertebrates, including plankton. Royal Blue tangs play an important role in maintaining the health and balance of coral reefs. Herbivores graze the algae (seaweed) on reefs, similar to cattle or sheep in a field. These herbivores keep the algae in check and keep space open for corals to grown and settle. Without herbivores, algae can overgrow and crowd out corals.

Coral reef structure is important to blue tangs who hide in coral branches, crevices and holes to avoid predators like groupers, bar jacks and tuna.

Despite how endearing Dory might appear in the movies, the real blue tangs do not make good pets because they need large tanks (which are expensive), a carefully balanced diet, and they are susceptible to disease—therefore they need very experienced aquarists to take care of them. Because this species cannot be bred in captivity, they are currently collected from coral reefs and there is concern that increased demand as a result of Finding Dory will put too much pressure on wild populations. For all these reasons, this species is better left on a reef or enjoyed at a responsible public aquarium.