Species: Acanthurus chirurgus
Last time on Doctor Who, the Doctor was mortally wounded and forced to regenerate…again. This time, though, to everyone’s surprise and horror, the Doctor turned into a fish. And not just any fish, but the tropical surgeonfish known as the Doctorfish—bum bum buuuuuuuuuuuum!
For those of you who don’t know, I’m a giant nerd, and I laughed way too hard when I realized that I could combine Acanthurus chirurgus with Doctor Who. I have no shame—most of the time.
Anyways, the Doctorfish is a type of surgeon fish that inhabits coral reef areas and can be commonly found in Florida, Bahamas, and the Caribbean. They can also be found in the waters of the Gulf of Mexico, north to Massachusetts, south to Brazil, your neighbors’ exotic aquarium, and the tropical waters of West Africa.
Color is not always an easy way to identify these Doctorfish because they can range from bluish gray to dark brown, and they can pale or darken dramatically between individuals. The major way to identify them while diving is by looking at the body; all doctorfish have 10‒12 vertical bars between their head and their tail. They also have distinct markings around their eyes, almost like flashy eye make-up.
Acanthurus chirurgus are herbivores that feed on algae, and they even have special teeth that allow them to pick off the algae growing in the sand, in rocky areas, and even on coral. In fact, these guys are really important to reef health because they can consume the algae that grow on coral, which would otherwise smoother the coral and their best friends, the zooxanthellae.
The origin of their common name is pretty cool. A. chirurgus have spines on either side of their caudal peduncle, or the base of their tail, that were discovered to be really sharp like a scalpel that doctors use. When feeling defensive, surgeonfish will use those spines as weapons by slashing their tails side to side at their aggressors.
Typically, Doctorfish will keep their distance from divers and will try to stay away if approached. However, people handling these fish can get serious injuries which are often quite painful and can lead to serious infection, especially since there is a crazy amount of bacteria and viruses in a single drop of water! So please be careful when diving with or handling doctorfish!
They are a common fish species found in private aquariums, and while they are not considered to be at risk of becoming endangered, you should still be aware of how they are caught and sold before purchasing individuals for your aquarium.
The doctorfish was one of the fish species I had to learn to identify for my Coral Reef Ecology class in college. I’ve seen them a handful of times when diving around reefs, and I’ve even watched them eating the algae from the coral, which was pretty cool to witness. I’ve read that you can eat Doctorfish, but I won’t try that because of the slight chance of getting ciguatera poisoning—which I’ll save for another ramble!
Sources and cool links:
Reef Fish Identification: Florida Caribbean Bahamas 4th ed. By Paul Humann and Ned DeLoach