Blue Tang Facts Habitat, Diet, Behavior

The blue tang is among the most common aquarium fish species. Its popularity soared after the release of the 2003 movie Finding Nemo and the 2016 sequel Finding Dory. These colorful animals are native to the Indo-Pacific, where they can be found living in pairs or small schools in the reefs of Australia, the Philippines, Indonesia, Sri Lanka, and East Africa. Fast Facts: Blue Tang Common Name: Blue tangOther Names: Pacific blue tang, regal blue tang, palette surgeonfish, hippo tang, blue surgeonfish, flagtail surgeonfishScientific Name: Paracanthurus hepatusDistinguishing Features: Flat, royal blue body with black palette design and a yellow tailSize: 30 cm (12 in)Mass: 600 g (1.3 lbs)Diet: Plankton (juvenile); plankton and algae (adult)Lifespan: 8 to 20 years in captivity, 30 years in the wildHabitat: Indo-Pacific reefsConservation Status: Least ConcernKingdom: AnimaliaPhylum: ChordataClass: ActinopterygiiFamily: AcanthuridaeFun Fact: At present, all blue tangs found in aquaria are fish captured in the wild. While children may know the blue tang as Dory, the fish has many other names. The animals scientific name is Paracanthurus hepatus. It is also known as the regal blue tang, hippo tang, palette surgeonfish, royal blue tang, flagtail tang, blue surgeonfish, and Pacific blue tang. Simply calling it a blue tang can lead to confusion with Acanthurus coeruleus, the Atlantic blue tang (which, incidentally, also has many other names). A Fish with Many Names Humberto Ramirez / Getty Images Appearance Surprisingly, the blue tang isnt always blue. An adult regal blue tang is a flat-bodied, round-shaped fish with a royal blue body, black palette design, and a yellow tail. It reaches 30 cm (12 inches) in length and weighs around 600 g (1.3 lbs), with males typically growing larger than females. Humberto Ramirez / Getty Images However, the juvenile fish is bright yellow, with blue spots near its eyes. At night, the adult fishs coloring turns from blue to violet-tinged white, probably due to changes in its nervous system activity. During spawning, adults change color from dark blue to pale blue. The Atlantic blue tang has yet another color-change trick: Its biofluorescent, glowing green under blue and ultraviolet light. Diet and Reproduction Juvenile blue tangs eat plankton. Adults are omnivorous, feeding on some plankton as well as algae. Blue tangs are important for reef health because they eat the algae that could otherwise cover the coral. During spawning, mature blue tangs form a school. The fish suddenly swim upward, with females expelling eggs above the coral while males release sperm. Around 40,000 eggs may be released during a spawning session. Afterward, the adult fish swim away, leaving tiny 0.8-mm eggs, each containing a single drop of oil to keep it buoyant in the water. The eggs hatch in 24 hours. Fish reach maturity between nine to 12 months of age and may live up to 30 years in the wild. Sword Fights and Playing Dead Blue tang fins contain spines sharp enough to be comparable to a surgeons scalpel. There are nine dorsal spines, 26 to 28 soft dorsal rays, three anal spines, and 24 to 26 soft anal rays. Humans or predators foolish enough to grab a regal blue tang can expect a painful and sometimes venomous stab. Male blue tangs establish dominance by fencing with their caudal spines. Although they are armed with sharp spines, blue tangs play dead to deter predators. To do this, the fish lie down on their side and stay motionless until the threat has passed. Ciguatera Poisoning Risk Eating a blue tang or any reef fish carries the risk of ciguatera poisoning. Ciguatera is a type of food poisoning caused by ciguatoxin and maitotoxin. The toxins are produced by a small organism, Gambierdiscus toxicus, which is eaten by herbivorous and omnivorous fish (such as tangs), which in turn may be eaten by carnivorous fish. Symptoms may appear anywhere from a half-hour to two days after eating an affected fish and include diarrhea, low blood pressure, and reduced heart rate. Death is possible, but uncommon, occurring in one in 1,000 cases. Regal blue tangs are strong-smelling fish, so its unlikely a person would attempt to eat one but fishermen use them as baitfish. Conservation Status The regal blue tang is not endangered, classified as least concern by the IUCN. However, the species faces serious threats from habitat destruction of coral reefs, exploitation for the aquarium trade, and use as bait for fishing. To catch fish for aquaria, the fish are stunned with cyanide, which also damages the reef. In 2016, researchers at the University of Florida bred blue tangs in captivity for the first time, which raised the hope that captive-bred fish may soon be available. Sources Debelius, Helmut (1993). Indian Ocean Tropical Fish Guide: Maledives [i.e. Maldives], Sri Lanka, Mauritius, Madagascar, East Africa, Seychelles, Arabian Sea, Red Sea. Aquaprint. ISBN 3-927991-01-5.Lee, Jane L. (July 18, 2014). Do You Know Where Your Aquarium Fish Come From? National Geographic.McIlwain, J., Choat, J.H., Abesamis, R., Clements, K.D., Myers, R., Nanola, C., Rocha, L.A., Russell, B. Stockwell, B. (2012). Paracanthurus hepatus. IUCN Red List of Threatened Species. IUCN.