Fish of the Week -----Paracanthurus hepatus (pacific blue tang)


Sir Brian The Lenient
Staff member
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This is a new series of informative threads conceived by Dave (see It is designed to give information about a different fish each week. The information given will be a combination of the "technical" side from research sources and the "real world" side from reefer's actual experiences.

Paracanthurus hepatus aka regal tang, pacific blue, blue

One of the surgeonfishes (tangs), the p. hepatus has long been a favorite of reef keepers. It is a beautiful fish, with bright blue and yellow markings. The hepatus acclimates very well to aquarium foods, and will accept frozen brine, mysis, plankton, as well as flaked foods. It also benefits from dried algae being made available for grazing.

Tangs (the hepatus included) are succeptible to skin diseases and parasites (such as ich). Also, head and lateral line erosion is not uncommon among tangs.

The hepatus is considered reef safe, and usually gets along well with tank mates, with the possible exception of closely related fish. Juveniles will normally school together, but adults may fight if they are not given ample room to spread out.

The hepatus tang can reach 12 inches in length, and a full-grown adult should have a large tank, since they are active swimmers. They also love to hide, so to minimize stress they should never be kept in a barren tank. They also frequently will wedge themselves tightly in the rockwork, seemingly stuck, only to pop out when they are ready.
Personal experience, as a follow-up:

I have 2 hepatus tangs in my 180 gallon reef. They were purchased as quarter-sized juveniles, and were captive-raised, not wild caught. They have experienced very different growth. One is about 6 inches long, and the other is probably a good inch smaller. I have had them about 1 year.

Food choices in my tank

They live a 180 gallon reef with lots of rockwork. They have always had big appetites, and will eat Formula 1 and 2, frozen msysis, plankton, and enriched brine. They also like all flaked food I have put in the tank. Mine won't eat frozen bloodworms, the one food they dislike.

Interraction with other fish

They coexist in my 180 with a zebrasoma veliferum (pacific sailfin tang) and a zebrasomo xanthurum (purple tang). The sailfin tang is the largest tang and dominates the tank, but all the tangs get along with minimal posturing or fighting. They don't bother (or are bothered) by any other tankmates, included wrasses and clownfish.


The hepatus spend most of their time in my tank hiding behind their favovite rocks, but come out readily when I feed the tank. I find the more often I feed the tank, the more they swim in the open (I think they are afraid they will miss a meal). They are a gorgeous fish, and easily the favorites of most who see my tank.
This species probably has more "common" names than any other fish in the aquarium hobby. Some of the names used to refer to this species are: Hippo Tang, Regal Tang, Pallete Tang, Hepatus Tang, Pacific Blue Tang, Blue Hep, and sometimes just Blue Tang (which makes it easy to get it confused with the Atlantic Blue tang, which is a different species.)

I mention this for all of you just beginning to research tangs because all of these different names used to confuse the heck out of me.

[This message has been edited by Deacon (edited 08-01-2000).]
Alright Brian! What a great set of threads to achive!
I got tons of books--but it seems the folks here have really guided me, at least on most things.
My "hippo" tang died after 10 days.
water parameters-name it, all good
reef tank
had yellow tang, firefish, bi-color blennie, false percula, dragon goby, flame angel, 6-line wrasse, jawfish;
Tank has lots of macro algae, I feed it alot-use ro/di water. About 10 species of corals, about as many of other invertabrates.
The regal got ich about after 5-6 days, no one was bothering him, eating fine every meal.
The regal died at day 10--eating to the end. The blennie got the ich (had it for 2 months) as well as the 6-line(had it for 3 months)=both of them sucumbed 3=4 days later.
None of the other fish even blinked!
Beautiful fish. How do you do it right?
Thanks again, Brian.

Pi - Formerly known as 'the quantity which, when the diameter is multiplied by it, yields the circumference.'
Smithsonian, May 2000
Hi bmw, thanks for the comments.

As with many fishes with poor survival rates, the hepatus tang often suffers from collection and shipping practices. The fish is already succeptible to parasites, and considering the conditions they are shipped in, it is likely they will develop problems.

The hepatus tangs I have were captive-raised, which means they weren't pulled from the ocean a week before they went into my tank. No drugs, cyanide, or any other nasty collection practices. I think that has quite a bit to do with their health. I strongly, strongly encourage anyone wanting to acquire a hepatus tang to look for captive raised specimens.

BTW, I have never had any parasites or ich on any of my tangs. I think with the proper tank conditions they don't need the hodge-podge of treatments different people promote. A good, stress free environment with vitamin enriched food should allow most fish to overcome the little "sniffles" that come their way.

Where do you get captive raised?

Pi - Formerly known as 'the quantity which, when the diameter is multiplied by it, yields the circumference.'
Smithsonian, May 2000
What has been yall's experience with the less common color variation as pictured on the cover of the Burgess atlas? Anybody know of a place that sells this variety?
Hiding places can't be stressed enough. I have had my Hepatus for 15 months so far, and it is the only fish who has had ick. Symptoms appeared several times after significant rearranging in the tank, especially if it involves the "cave". Symptoms would naturally clear a few days after the disturbance.

Speaking of a cave, the hepatus first had a home wedged between two rocks at the bottom center of the tank. The dominant Yellow Tang owns most of the tank (probably has a territory twice that big in nature) but had no interest in this fissure.
Feeling sorry for the fish being so cramped, I opened up its area to a nice sized cavern. Hep didn't like it any more, and found a new spot to wedge itself into. The Yellow tang took over the condo.

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bmw, I purchased my hepatus from Inland Aquatics. Note that they are called captive raised, not tank raised.

A few months ago someone posted a very detailed explanation of this procedure (captive raising saltwater fish). Maybe someone will jump in here.

One more comment here :) I've had a Hippo for a couple of years now - I believe he got through the initial introduction to the tank without illness because I had a couple of cleaner shrimps already there. He looked shaky for the first few days (very nervous and scratched on the rocks) but visited the shrimps for a cleaning about every hour.

I don't think I'd introduce a new tang or do any major renovations in my tank without the shrimps as a safeguard - can't hurt ;)

I have a juvernille Paracanthurus hepatus for about 4 weeks now. It is approximately 1.5" long. The first week I got him, he hide all the time, after then he start roaming the tank and eat normally. However, I also noticed that he has develop a chronic ich problem - it niether get worse nore better, he has a decent amount of the white spot on his body, and his eyes are a bit cloudy. Also, I see black spots on him too which comes and go.

He has been like this for 2-3 weeks now, but like I said, it hasn't gotten any worse/better. I fed him with selcon/ZOE/spirulina and live seaweeds daily - but it doesn't help.

Should I Q him and start the medication?
Great start to the series Brian :)

My Hippo has been with me for over a year and half now and shares the tank with a Naso, a pair of ocellaris clowns, Centropyge argi, and an orchid dottyback. This fish is most definatly a hog! Eats anything and everything I throw in. Based on my experience with these guys, and other tangs, over the years I would say the most important consideration for thier diet is to provide lots of algae along with a variety of other foods.


If damsels grew as big as sharks, the sharks would run in fear!
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I've had my hippo for almost 2 years now. He's in a 220 reef with a purple, chevron and powder blue. The hippo was added first along with the chevron, the purple and powder were added about 6 months later together. The hippo has never been bothered by or bothered the other tangs except for the occasional tail swipe when they are feeding and get too close to each other. Defenitely most peoples favorite including my wife's.


I have 5 Blue Tangs in total, 4 in my 190 and one in a 50. 3 of the 4 in t 180 I will have had for 2 years in 2 weeks time. The 4th I've had for 18 months. The first 3 were 25, 30 and 40mm respectively when I got them and were added to a 50 just after it had cycled. They were eating very well from day 1 and survived on flake food for 2 weeks while I was on vacation, less than a month after I got them. They were moved to the 180 just over 18 months ago. The 4th one was 25mm when I got it. They are now 100, 120, 130 and 80mm respectively.

They once had a bout with "Ich" which I put down to temperature fluctuations. I installed fans in the hood, the temperature stabilised and the "Ich" went away. I have a large Acropora skeleton that all 4 hide and sleep in.

The Blue Tang in my 50 is a real odd fish. When I first got it, it was 30mm. In the quarantine tank it used to "hide" up against the front glass, even though there were more than enough hiding places in the tank. It now likes to hide in tight crevices. I've had this one just on one year.

All 5 are very skitty fish - these are the chicken little of the fish world. I'm sure all the other fish hate them due to there "oh my God" attitude to everything.

They eat anything and everything.

Hi Brian :)
Here goes.
I've had one pair of P. hepatus for about three years, and my husbandry experience with them goes back more than ten.

It is important to remember that these fishes when young really need refuges. In the wild the young can be found living in sand burrows or rubble nests, sometimes with commensals (shrimp, etc.), quite often in small groups.

Their juvenile tenancy on the warm reef is succeeded by a semi-pelagic, schooling existence. This has direct bearing on tank temperature, as schools can travel well below 50 metres depth off a reef face: best to keep the tank on the cool side of 80F IMO.

Regarding the semi-adult urge to seek open water, I think it's possible that tank confinement of tangs in general either arrests this behavioral progression (like canine arrested developent), or can induce a psychotic territoriality --which P. hepatus seems, happily, one of the most under-equipped of the tangs to vent upon tankmates.

While the softer algae in-tank has been sufficient to keep my blue grazers alive, they also relish most flake foods, and don't mind fresh marine protein. I would keep this fish in as large a tank as I could afford.

Easily spooked? I agree, but for it to succumb to disease? I had one of the pair flopping about on the garage floor, and that was a year and a half ago. It's my favorite little buttkicker today (the other fish is more of a wuss, but bigger). Dunno what makes 'em fragile in some tanks, unless they're already borderline psychotics.

One of my all-time favorite fish.
Even on the dinner table.


PS: Deacon, you can add 'Labahitang asul" to the list of common names, unless English alone is being counted :)