Pacific Blue Tang Fish “Paracanthurus Hepatus”

Pacific blue tang fish

The Pacific blue tang, or paracanthurus hepatus, is a colorful fish that can be found in the Indian and western Pacific Oceans. It has many different color variations, which include blue, green, yellowish-brown, and white. The colors vary depending on where it lives as well as its age. Juvenile Pacific blue tangs are a lighter color than the adults.

Pacific blue tangs can grow up to 18 inches in length and weigh up to four pounds. They have a deep, compressed body with a small head and two dorsal fins that run the length of their bodies. Their tails are forked and they have a single anal fin.

The Pacific blue tang is a herbivore and feeds on algae, seaweed, and small invertebrates. They are often found in pairs or small groups.

They are popular aquarium fish and can be bred in captivity.

Origin and descriptions

Pacific blue tang fish

The Pacific blue tang is a fish in the genus Paracanthurus and the family Acanthuridae. It was first described by French naturalist Charles Lucien Bonaparte in 1831 and named after his older brother: Emperor Napoleon I of France (1769-1821). The species can be found in tropical marine waters throughout the Pacific Ocean, from southern Japan to New Caledonia.

The generic name, Paracanthurus, comes from the Greek words para (meaning beside) and kantharus (meaning a fish with a prominent red spot on each side of its body). The specific epithet, hepatus, is derived from the Latin word hepar (meaning liver) in reference to the species’ greenish-brown coloration.

Pacific blue tangs are one of the few marine fish that can tolerate changes in water temperature and salinity. They have been known to inhabit both fresh and saltwater environments.

The body of a Pacific blue tang is deep blue with a yellow tail and dorsal fin. The fish can grow up to 45 cm (18 in) long, though most only reach about 30 cm (12 in). Juveniles are black with white stripes running lengthwise down their bodies.

They are herbivores, feeding mainly on benthic algae. They will also consume zooplankton and other small invertebrates. The fish is an important part of the coral reef ecosystem, playing a role in both predator and prey populations.

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Species profile

Pacific blue tang fish

The Pacific blue tang is the most common of the surgeonfish family. It has a deep blue body with yellow accents on its tail, head, and dorsal fins. This species can be found in tropical reef areas throughout the world including Hawaii, Fiji, Australia, Tahiti, and Western Africa. They are nocturnal predators which feed at night on small invertebrates, algae, and zooplankton.

Scientific name

The scientific name for the Pacific blue tang is Paracanthurus hepatus

Color and appearance

This species of tang is brilliant blue with yellow accents on its tail, head, and dorsal fins. It has a black stripe running from the eye to the base of the pectoral fin (which extends along most of this fish’s body) – like many other surgeonfishes.

It has a tall, straight first dorsal fin and the caudal fin is truncated. This species can reach up to 20cm in length as adults – but they are usually around one inch at birth.

The Pacific blue tang reaches sexual maturity at six months of age and breeds year-round – particularly during the warmer seasons when algae growth is high. They are hermaphrodites having both male and female reproductive organs.

Range and habitat

This species of tang is most commonly found in tropical reef areas throughout the world including Hawaii, Fiji, Australia, Tahiti, and Western Africa. They prefer shallow waters with clear visibility, but will also be found at depths up to 100m below sea level.

They are nocturnal predators which feed by night on small invertebrates such as copepods and algae.

Pacific blue tang size

The Pacific blue tang can grow up to 20cm in length as adults but is usually around one inch long at birth.

Pacific blue tang tank size

A 30 gallon tank is the minimum size required for a single Pacific blue tang.

Life cycle

The life of a Pacific blue tang is relatively short. They typically only live for around five years in the wild, although they may live up to ten years in captivity. The main cause of death for these fish is predation by larger fish or seabirds.

Pacific blue tangs undergo an elaborate spawning ritual before mating. The male and female swim in a circular pattern while they release sperm and eggs into the water. This fertilization takes place externally, with no parental involvement after mating occurs.

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The blue tang spawns year-round; however, spawning is more common during warmer months of the year when there are ample amounts of food available to support both parents as well as their offspring.

The eggs hatch in about two days, and the larvae are planktonic for around five weeks. After that time, they settle at the bottom of the ocean where they will live out the rest of their lives.

Are they aggressive or peaceful?

Pacific blue tangs are generally considered to be peaceful fish. They tend to avoid confrontation and pose little threat toward other species of fish or humans. However, they may become aggressive if their habitat is overcrowded, as this can create tension among the inhabitants in an aquarium setting.

These captive situations usually lead to aggression between two different individuals rather than between a fish and a person, although it’s possible for blue tangs to become aggressive towards their owners.

If you have multiple specimens in your aquarium, you should ensure that there is plenty of space included so they don’t feel crowded or stressed out.

Pacific blue tang care

Pacific blue tang fish

The Pacific blue tang is one of the most popular saltwater aquarium fish. They are bright and colorful, and they grow to a large size. Because they are so popular, they can be expensive to buy from a pet store.

Pacific blue tangs need a lot of space in an aquarium, and they require a lot of food. They are also very sensitive to water parameters that might not be ideal for their health. This means they need a lot of care, and people should study up on the best way to keep them before making the investment in having one as a pet

One thing that makes blue tangs different from most other saltwater fish is their eating habits. Many saltwater fish are omnivores, which means they will eat both plants and meat. But the blue tang is a herbivore, meaning it only eats plants. This can make it difficult to care for them if their diet is not properly supplemented

What they eat

Blue tangs eat algae, including bubble algae or caulerpa taxifolia. You can buy these plants for your aquarium if you are trying to feed the blue tang. Blue tangs also like squid and shrimp in their diet, but they can’t survive on meat alone. They need a lot of plant matter as well

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You should only feed your blue tang as much food as it can eat in two minutes. If there is food leftover after two minutes, you are feeding the fish too much. This can lead to health problems down the road

Tank mates

Pacific blue tangs can sometimes be aggressive fish, and they will not get along with other fish of the same size. If you want to keep more than one blue tang in your tank, you need to make sure that they are different sizes. Otherwise, the smaller ones will become food for the larger ones

If you are looking for a compatible fish to keep with your blue tang, try a damselfish or goby. These fish are small and will not be seen as a threat by the blue tang

Water conditions

You should keep your blue tang in water between 72 and 78 degrees Fahrenheit. The pH level of the tank should be at around eight point five, but it can vary depending on where you get your saltwater from

Your blue tang will need a lot of oxygen to survive, so make sure that there is always some kind of air stone or bubbler in the tank. You should also change at least 25 percent of the water in the tank every week to keep it healthy


Pacific blue tang fish

The breeding of Pacific blue tangs is a delicate process that can be difficult to achieve in captivity. In order for them to breed, the water temperature must be between 75 and 82 degrees Fahrenheit, and the pH level must be maintained at around an alkaline eight or nine. Additionally, the tank must have plenty of live rock for the fish to hide in, as they are shy creatures.

If all of the necessary conditions are met, the male and female will begin to court one another. The courtship process can last for several days, and is characterized by the male chasing after the female and nudging her gently. If she is receptive, she will eventually allow him to mate with her.

After the mating process is complete, the female will lay her eggs in a sheltered spot on the live rock. The eggs will incubate for about ten days before hatching. Once they have hatched, the baby fish will be completely dependent on their parents for food and protection until they are large enough to fend for themselves.

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Pacific blue tang lifespan

The average lifespan for a Pacific blue tang is about eight years. However, some specimens can live up to ten or fifteen years in captivity if given proper care and nutrition.

Parasites and diseases

Pacific blue tangs are susceptible to a wide variety of parasites and diseases. Some of the most common ones include:

  • Hexamita (a parasitic infection)
  • Brooklynella (fluctuating white spots on skin, mouth, and fins)
  • Ascites (abnormal fluid accumulation in the body cavity)
  • Cryptocaryon (marine white spot disease)
  • Sargassum fluitans (parasitic infestation of gills)
  • Mycobacteriosis (causes granulomas on body and fins)

If you notice any of these symptoms in your Pacific blue tang, it is important to take them to a fish veterinarian as soon as possible.


The predators of the Pacific blue tang are many and varied. Large fish, such as barracuda and sharks, prey on them as do marine mammals, such as seals and dolphins. Seabirds also hunt them. Some parasites also prey on the Pacific blue tang. The most common parasite is a dinoflagellate called Ichthyophonus hoferi. This parasite attacks the liver and causes lesions that can be fatal if not treated.

The parasites of the Pacific blue tang are also varied and include flukes, tapeworms, and nematodes. Some of these parasites are transmitted by snails, others by copepods. The most common is a protozoan called Tetrahymena thermophila.

Does it make good pets?

The Pacific blue tang, also known as the regal blue tang or hippo tang, is not a good fish for beginners and experts alike because of its specific dietary needs and complicated care requirements.

In the wild, their natural diet consists of crustaceans that have high levels of Omega-three fatty acids which is necessary for growth.

They require an experienced person who can provide clean water with plenty of natural sunlight and space in order to thrive. It’s best left to those who have the time, resources, and knowledge to care for one of these fish.


The Pacific blue tang is a beautiful and interesting fish that can be found in the wild in many tropical areas.

They are not recommended as pets for most people, however, because of their complicated care requirements. Those who have the time, resources, and knowledge to provide for one of these fish will be rewarded with an amazing pet.