Pacific Blue Tang: Paracanthurus hepatus

Phylum: Class: Order: Family: Genus: Species:
Chordata Actinopterygii Perciformes Acanthuridae Paracanthurus P. hepatus

Common Names: Pacific Blue Tang, Hippo Tang, Royal Blue Tang, Regal Tang, Yellow-tail Tang, Hepatus Tang, Palette Tang, Blue Palette Tang, etc.

‘Surgeonfish’ is sometimes used in place of ‘Tang’ in any of the common names used.   Less commonly used is the term ‘Doctorfish’.   P. hepatus has perhaps the most confusing list of common names of any fish in the hobby.   Pacific Blue Tang or Hippo Tang are perhaps the most common names used.  The name Blue Tang is also shared with other Tangs that more rightfully deserve that name since they are a solid blue.

Scientific Name:  Paracanthurus hepatus

Pacific Blue tangs are a very colorful light to medium blue with a prominent yellow tail.  There is a black line that extends from the eye along the contour of the back to the tail.  A second black line extends from behind the gill slit back to the tail.  The black extends the length of the tail on both the top and bottom edges.  the dorsal and anal fins are also edged in black.  The pectoral fins have some yellow coloration.  Their body is oval and flattened.  They have a yellow spine on the side of their body near their tail that they use for defense and offense.

Adults develop a red tinge to the dorsal fins that is noticeable when the dorsal fin is displayed.  A whitish spot may develop on the side of the fish.  As the fish ages, dots similar to freckles form on the face and become more prominent.

Natural Environment:
Found on reefs in the Indo-Pacific usually in higher current areas where they forage on zooplankton.  Most commonly observed as solitary individuals though they sometimes form into loosely formed groups while feeding.  During mating, small harems will form with one male and several females.  Juveniles are usually found in groups near SPS coral heads where they can hide when alarmed.

Reef Tank Suitability:
Pacific Blue tangs are very good reef tank inhabitants for larger tanks of about 120 gallons or larger for a single specimen and is one of the most popular fish for larger reef tanks.

Pacific Blue tangs are generally peaceful community fish, but will quarrel with others of their own species when adult, so only one should be kept per tank unless the tank is quite large (180 gallons or more) and the fish are all introduced at the same time.  Small juveniles may be kept in groups in smaller tanks, but this is a temporary arrangement at best.  They like to wedge themselves into a hole in the rockwork when they sleep at night. They are nervous fish and frighten relatively easily.  Having a safe place to sleep or hide will help them feel more secure.

Pacific Blue tangs enjoy a more meaty diet than many other tangs and tend to not be picky eaters.   Any standard frozen meaty foods such as Mysis shrimp, Formula One and bloodworms are readily taken.  It is generally recommended to include some vegetable matter in their diet as well such as Nori seaweed, but mine have generally not eaten it.  A varied meaty diet helps to ensure that they remain healthy.

Pacific Blue tangs have the nick-name of ‘Ich Magnet’ for good reason.  They seem especially prone to contract the Ich parasite when stressed and it is not uncommon to have them come down with a case shortly after introduction into a new tank.  While stressful to the hobbyist, this often seems to disappear of its own accord in a reef tank that has good water quality and if the fish is in otherwise good condition.  Once acclimated, they tend to be fairly hardy and long-lived fish if they are feed properly.  They are susceptible to Head and Lateral Line Erosion (HLLE) and the best defense appears to be good nutrition which a varied diet helps ensure.

Does well within normal reef tank temperature ranges of approximately 74-84°F.

Pacific Blue tangs can get up to about 12″ in length in the wilds and will typically reach 8-10″ in captivity depending on tank size and feeding.  As noted above, a tank of approximately 120 gallons should be considered the minimum size to house the Pacific Blue tang to adulthood.

Pacific Blue tangs are not breed in captivity at this time.  Their large size, breeding habits of forming harems during breeding season and the fact that their eggs are broadcast into the water column would make them very difficult to breed in captivity.

Almost as good however is that many are captured as young larval fish and then captive-raised to a size of approximately 1.5″ for sale into the hobby.  Since most larval fish don’t survive in the wild, this practice probably has a very small impact on the native populations compared to the capture and sell of wild caught adult fish.  These captive-raised fish seem to transition to reef tank life very well and I highly recommend these to hobbyists as long as you don’t mind starting with a small specimen and waiting a couple of years for it to grow out.

 Header photo courtesy of Holger Krisp, Ulm, Germany.  All other photos by ReefCorner © All Rights Reserved