Has anyone seen Finding Dory yet? I haven’t, but when I was trying to think of a fish to write about this morning, I saw a post online about the movie. Problem solved! Today we’ll talk about the blue tang, also known by a myriad of other names, including regal tang, palette surgeonfish, hippo tang, and doctorfish.

Blue tangs are marine fish, and live in the Indo-Pacific Ocean. They live in and around coral reefs, in tropical and sub-tropical areas, where temperatures stay between 24 and 26 degrees Celsius. They are found in reefs along the coast of East Africa, Japan, Samoa, New Caledonia and the Great Barrier Reef.

You have probably seen blue tang fish; they are very recognizable, with bright blue bodies, black stripes, and yellow fins. They can get to be 30 cm long, with males being larger than females. Young blue tangs are more yellow than blue, and darken to full blue as they mature.

A very pretty blue tang. Image by Tewy, CC BY-SA 3.0, via Wikimedia Commons

Blue tangs are targets for some marine predators, such as tuna and tiger groupers. They will often school together in reefs, sticking close to other blue tangs for protection. This is especially effective because each blue tang possesses a razor sharp caudal spine. These can be extended when the fish feel threatened, meaning that a predator swimming into a school of blue tangs would have to deal with a bunch of fish, all with super sharp spines. Not a smart choice.

The tangs also have less aggressive methods of dodging predators. They can change their colour, making themselves darker or even semi-transparent to hide themselves in the reefs. They will also play dead, lying still until the predator moves on.

Blue tangs will either breed in groups or in pairs. In both cases, they swim towards the surface before releasing eggs and sperm into the water. This is thought to help with dispersing and mixing the gametes. The eggs will hatch in the next 24-28 hours, and grow quite quickly. They become mature at 11-13 cm in length.

Blue tangs are very pretty fish, and Dory is a great character. But they are quite fragile in captivity, and are not known to breed in tanks, which means all blue tangs are wild caught. So I definitely wouldn’t want one as a pet, though I’ll certainly enjoy watching Finding Dory!

Cover image by Karelj, CC BY-SA 3.0, via Wikimedia Commons, cropped to fit