surgeon fish (Acanthuridae) is a deep-bodied tropical marine fish of the family Acanthuridae (order Perciformes). Surgeonfish are small in scale, with a single dorsal fin and one or more distinctive, sharp spines that run on either side of the base of the tail and can produce deep cuts. The spines, which resemble a surgeon's scalpel, can be pinned in place or hinged at the back so that they can open outward and be directed forward.


There are approximately 80 species of bright surgeonfish that inhabit the oceans. They are typically small and slender, but the largest species can reach a length of one meter. Its half-life is 25-30 years. Common saltwater species include:

  • Yellow surgeonfish (Zebrasoma flavescens)
  • Blue surgeon (Paracanthurus hepatus)
  • Sky blue surgeonfish (Acanthurus leucosternon)
  • Clown surgeon (Acanthurus lineatus)
  • Convicted surgeon ó lined (Acanthurus triostegus)
  • Orange thorn unicorn fish (Naso lituratus)
  • Surgeon on (Acanthurus aquilles)
  • Yellow-eyed surgeonfish (Ctenochaetus strigosus)
  • Yellowtail surgeon ó purple surgeon (Zebrasoma xanthurus)
  • Acanthurus japonicus
  • Zebrasoma desjardinii

There are many more with different colors and markings, but these are the most common and the most famous in aquariums.


Identified by their bright color, oval bodies, and flag-shaped tails. Their pectoral fins are also yellow. Adults have a narrow dark line along their dorsal fin that curves backward at the tail.

The coloration changes as they mature, according to the Animal Diversity Network (ADW). Young blue surgeonfish are bright yellow with blue eye spots, and their fins have light blue tips. Their bodies turn blue as they mature.

The blue surgeonfish is also known as the fish with the number 6.

The blue surgeonfish is also known as the fish with the number 6.

Surgeonfish get their name from the scalpel-shaped spines along the top and bottom of their bodies. These fish have a sharp, poisonous spine at the base of their tail fin, or tail fin, to protect themselves from predators. The caudal column contains a toxin that can cause severe pain to both small predators and humans.

Adult fish usually weigh around 600 grams and are 12 to 38 centimeters long. Males are typically larger than females.


These fish are somewhat social and are usually found in pairs or small groups. They often form colonies with 10 to 12 members. Not only do they hang out with their own kind, in fact several different species of surgeonfish can be found in their schools.

When faced with a predator they often "play dead" lying on their side and remain motionless until the predator passes them.

Males are often aggressive towards each other, having "sword fights" with their tail spines. They manage to dominate this way, and the more dominant males have larger breeding areas, according to the ADW.


Their homes are the coral reefs that grow along the coasts. They especially like to hide in the protective branches of cauliflower coral. They are found in all the temperate and tropical oceans of the world.


These fish live in the Pacific Ocean, but are also found in the Indian Ocean, from East Africa to Micronesia, according to the International Union for Conservation of Nature (IUCN).

Yellow surgeonfish.

Yellow surgeonfish.


These fish typically feed on algae, using their sharp little teeth to keep their coral protectors clean.

These fish are very important to the life cycle of the coral reef. They eat up the excess algae on the reef, which prevents the coral from suffocating. Coral reefs are home and food for around a quarter of all ocean species, even though they cover less than 1 percent of the Earth.


Surgeonfish predators include snapper, grouper, horse mackerel, and barracuda. Even though surgeonfish are fast through the water, these fish still target surgeonfish due to their size and also because they are easier to catch than other fish.


When it's time to breed, these fish congregate in breeding groups. The females expel their ovules into the water above the coral, and the males expel the sperm, and fertilization occurs externally. About 40.000 eggs are shed per spawning session. After spawning, the "parents" swim, never worrying about their offspring.

The fertilized eggs are thrown adrift and become part of the plankton "soup". About 26 hours after fertilization, the eggs hatch and live in the soup until it is time to transform into young. At that time, they settle in a coral habitat, where they complete metamorphosis.

The babies are called larvae. Maturity is measured by size and not by age. Males are considered mature when they reach 11 cm in length; females when they are 13 cm long. Blue surgeonfish can live for more than 30 years in the wild.

Orange thorn unicorn fish

Orange thorn unicorn fish

State of conservation

According to the International Union for Conservation of Nature, these species are not in danger of extinction and are on the list of species of least concern. Their populations are widespread and the population is believed not to be declining.

There has been no successful breeding of blue surgeons in captivity; therefore, increased demand will necessarily lead to more fish being caught, which will reduce populations.

Popular culture

There is a character from a very famous animated film called Finding Nemo (Finding Nemo), which has as co-star a blue surgeonfish, named Dory, became so popular that they made their own sequel. Dory is a very optimistic and kind fish, but silly and with a bad memory. This is because you suffer from short-term memory loss. However, she has a heart of gold, and was willing to do whatever she could to help Marlin find her son (although she can never remember his name).

Dory is a blue surgeonfish

Dory is a blue surgeonfish

Relationship with humans

These fish are a popular aquarium species, and some environmentalists are concerned that these fish will fall victim to increasing popularity due to the movie, "Finding Dory." Other animals have suffered after being featured in recent movies.

Some call it the «Finding Nemo effect«. According to the Aquarium Welfare Association (AWA) after that film was released in 2003, demand skyrocketed and hatcheries were unable to keep up. They had to resort to buying wild captured specimens. This, in turn, led to population declines in several natural habitat areas.

Also, many people bought the clownfish without knowing how to properly care for them. Inspired by a scene in the movie, hundreds of children flushed their clownfish down the toilet in hopes of freeing them, according to the AWA.

List of other interesting animals