Alas... Another Sohal
First off I would like to say that I love your site, it is one of the most informative sites for the marine fish keeper that I have seen.  
<thanks kindly, my friend>
I am a 4th year marine biology student and the university of west Florida, but due to their lack of marine biology curriculum for undergrads I have to do most of my learning on my own.
<understood... and keep learning <G>>
I recently acquired a 3.5 inch sohal tang.  
<ughhh! I really wish pet stores would stop selling this beautiful fish. 2 foot long as an adult, most stunt and die prematurely in private aquaria. This is truly a public aquarium fish at best>
I have a 75 gallon tank, 4 feet long and 14 inches wide.  
<<<sobbing>> can't speak...>
The tank is currently populated with a small collection of LPS and polyp corals, a coral beauty angelfish, false percula,
regal blue tang (exact same size as the sohal),
<oh, geez>
Rainford goby,
<no really... just shoot me now. Rainford gobies categorically are one of the most difficult fishes for captivity... living on the infauna and epiphytic material of Derbesia algae! Adequate substitutes in captivity are not easily proffered. Most Rainford's eat well enough but still die in less than one year in captivity... very few live to see two. Unless yours is over two years old... please don't reply with "ya... but mine looks fine" <G>. Heehee...>
mandarin goby,
<with these last two fishes, you really MUST have a large fishless refugium plumbed upstream>
assortment of hermit and emerald crabs, and a harlequin
<Yowsa! Stop the presses... dude! You have a Tuskfish, blue regal tang and a sohal tang (with other fishes too!!!) that total a collective length of over 50" as adults!!!! You literally need to have a 600gallon tank to even be in the low end realm for keeping these fishes in the 5 year picture. Else, they will stunt and die prematurely like everyone elses>
and skunk cleaner shrimp (I am very happy with this assortment of fish, and do not plan to add any more).  
<I'm glad you're happy with your assortment of fishes... that makes one of us <VBG>>
I have a lot of live rock with healthy coralline algae growth. To my surprise, the sohal and the regal blue seem to be getting along beautifully with absolutely no aggression.  
<dude... your sohal is only 3.5 of 24" total inches and hasn't started sexually maturation yet. You have my sound promise that he will begin wrecking the tank and fishes in less than a year>
They even seem to bump casually sometimes while swimming, or when grazing on the same area on the live rock. However, given the Sohal's tendency for territoriality as he matures, I have a feeling that this is a peace that cannot last a very long time in my 75 gallon tank.  
<you said it brother!>
How long do you realistically think I could get away with housing this sohal in this setup?  
<that depends... what time does your watch say... >
Also, what size tank do you think I should upgrade to in order to house this community of fish for the next 5 to 7 years safely?
<Michael... do look up the adult sizes of these fishes on fishbase.org  
I would never recommend a Sohal for a small private display. What if you get a tank 10 feet long and 2 feet wide and 3 feet tall (400+ gall). That is still a tank that is only as wide as your fish is long and leaves a very short run for it to swim. Its the equivalent of a six foot tall man living his entire life in a living room sized space. Yowsa. My advice is to find a bigger home for the sohal tang and enjoy the rest of the fishes in a commercial 200-300 gallon aquarium>
Thanks, Michael McAllister
<best regards, Anthony>

Re: Acanthurus sohal housing
By harlequin I meant harlequin the shrimp, not the wrasse.  
<Yowsa... my bad! A big difference. Still.. do try to feed the harlequin shrimp with cultured Asterina stars or live-bearing brittle stars. It is horrible to buy wild sea stars like chocolate chips from the LFS no matter how cheap they are. The mortality on import for many of these sea stars is over 50% (with some at 90%!!!). So that means 5 to 9 stars die on import to get you one live one to feed the shrimp. Asterina are easy to breed like mad! Simply cut/frag them... you can get hundreds in weeks>
Not crazy enough to try housing a harlequin tusk wrasse with my defenseless corals and inverts.  
<bless you heart my friend.. although some folks keep young Harlequin wrasses in reefs>
What I should have said was that by happy with my assortment of fish I am aware that adding any more would probably make me overstocked to the point of having to deal with ammonia toxicity every 2 weeks.
<agreed <G>>
There is also a refugium running on the system that I built (24x12x12 inches,
<excellent!>
have  not bothered to calculate volume in gallons), the biggest that would fit under the stand. The mandarin has been fat and happy for about a year, so there definitely are plenty of critters in there to eat.  
<very good to hear my friend>
I know I will be upgrading to a 250 gal at minimum in they next year or two. I am fully prepared to pawn the regal blue the moment I see fighting, the blue would most likely be on the losing end.
<agreed>
My original plan was to sell the regal blue before getting the sohal.  The guy at the fish store said I should give them a chance to work it out first, or something to that effect, so I am giving it a shot.
<OK>
I may have bitten off more than I can chew with the sohal.  Maybe keeping my Goniopora alive for 3 and 1/2 years and counting gave me delusions of grandeur (it is throwing 3 buds, I am so proud).  
<excellent to hear... keep up the good work too>
Right now the tang is still in the wait and see phase.  I have seen differing accounts as to how large these Sohals can get when kept in captivity from a juvenile stage,
<please understand that the range in mature sizes is entirely dependent upon good or bad husbandry and tank size. The natural adult size of the fish cannot be changed. Definitive scientific studies have been done on this subject! And saltwater fishes (unlike freshwater fishes which are more inhibited in growth by competitive hormones) require long runs of space to swim. It has been demonstrated that fishes that survive in a 200 gallon long tank (say 10 feet long) will stunt and die prematurely in a 200 gallon tall tank (say 4 foot long). This is not a debatable subject... hobbyist accounts to the contrary are bunk and wishful thinking. If that crap were true we'd be seeing pygmy nurse sharks in 20 gallon aquariums <G>>
as well as differing accounts as to the level of their aggressiveness depending on whether the sohal is first or last into the tank.  
<also crap... the difference in aggression is determined by individual, not order of purchase. Science again>
Some people say up to 15 inches at a maximum, other places say 20, so its hard to know what to believe sometimes.  
<believe science my friend... human beings are likely to grow 5 to 6 feet tall. If they suffer kidney failure or other imposed complications in the developmental stages of life, they may not even reach 4 foot tall or live to see 40 years old. Half height and half life span is still an unrealized potential>
It seems like the people who have had the worst experiences with these fish tend to be the most vocal.  
<I cannot say that I've had a bad experience with this fish... but I talk to several people each month killing them in small home aquaria>
I guess my main question was how fast can I expect this fish to grow?  
<that will be relative to swimming space and otherwise good husbandry. Adult size in 5-7 years naturally at a modest pace. Can be realized in slightly less than five years with optimum care (big public aquaria)>
The tank is fed about 3 times a day, approximately enough for the fish to consume in 30 seconds.
<excellent! 3 or more feedings daily is quite helpful and healthy for fishes>
Thanks again. Michael McAllister
<best regards, Anthony>

Adding a Sohal Tang? (6/6/04)
Hello, <Hi. Steve Allen here tonight)
  I have a 14 month old 180 gallon (72x24x24) reef tank with 4700 gph  overall current flow.  Currently there is only one orange percula and one  black percula in the tank with future plans on adding two to three purple  Firefish and possibly a flame angel. <Light stocking.>  
  I have read your article on the Sohal and the FAQ's sections at  length, but still must ask you point blank.  Is my tank too small to  properly house a Sohal if it is the only other fish added to this tank?   Would it be aggressive toward the clowns and Firefish? <I think this is the real problem here. This Tang has nasty reputation for aggression & territoriality.> I am looking for a  nice show fish that is "out of the ordinary" to help finish off the reef and the Sohal came to mind. I have a friend with a 500 gallon that I can move him too when he gets over a foot long. <How about a nice little harem of fairy wrasses--a male and two RO three females in this size tank would be showy indeed.> Thanks in advance for you time. <Hope this helps.> Sean Jacobson

Sohal Tang addition?
Bob,
I have an existing reef tank of 180 gallons (36 deep, 36 wide, by 32 high)
<Interesting shape!>
with many corals, shrimp, two anemones, maroon clown 1-1/2", skunk clown 2", two domino damsels 2", two striped damsels 1", blue damsel 1-1/2", tiger Jawfish 3", red spotted Hawkfish 1-1/2", bicolor goby 1", pacific blue tang 3", asfur angel 6", with a large 20 gallon refugium, very strong water flow, at least 120lbs live rock, live sand.  How would a sohal tang fit in?
What else might work (how about a dwarf lionfish?)?  Thanks for your help, your articles are exceptional.
Charles
<Thanks and yikes re additions here Charles. The Asfur will very soon be about all that goes in this system... especially due to its physical dimensions... the Sohal I'd avoid due to very likely negative behavior with your other stock as it grows... and a Lionfish would too likely go undernourished with your present entourage. I would stick with what you have... and look into another tank... Bob Fenner>

Tangling With A Tough Tang! (Sohal Tang In Mixed Tank)
Hi crew,
<HI there! Scott F. here today!>
I would really love to get a Sohal Tang for my 180 tank. At the moment there is not much livestock in the tank, so I am just "planning" at this stage. But if I am to introduce a Sohal later then I need to plan for it now in the other fish I choose.
<Absolutely...these fishes have a well-deserved reputation for being rather poor citizens!>
Generally speaking, I am nervous about adding a Sohal simply because of the horror stories I have heard about them being so aggressive.
<These stories are usually true. These fish can be extremely nasty. Quite honestly, I would not attempt to keep one of these fishes in anything less than an 8 foot long aquarium, simply because they do reach considerable size, "patrol" a large territory, and need larger water volumes to keep up with the copious amounts of metabolic wastes that they produce. I'd rethink keeping this fish in a 180, myself.>
Ultimately, I plan on having an angel (maybe a Maculosus OR Passer), some other smaller tang (yellow - not another Acanthurus -maybe a Hippo???), and one other medium-bodied fish (non angel / tang).
<IN a large enough tank, you could certainly add another tang, but in a 180, it could be potentially problematic. Personally, I'd try another tang or two other than the Sohal in this sized tank. That's just me, but I've seen a number of Sohals "for sale or trade" locally that were in situations that just didn't work out.>
The tank is to be what I term a marginal reef set up - that is to say there will be hardy corals (Toadstool Mushroom, Star Polyps, and shrooms) - but nothing that could be termed as a reef tank as such.
<I nice setup for a fish-oriented display! Natural is always cool!>
Is a Sohal a good choice, or is there considerable truth to the scare mongering?
<Sadly, the truth really is that these guys are bruisers. I'd entertain other tangs in this setup...Much more appropriate for long-term success, IMO!>
Cheers, Matt
<Best of luck to you, Matt! Regards, Scott F.>

Sohal confusion  - 12/29/06
Hello,
<Hi Andy, Mich here.>
reading your sohal FAQs, and I am confused.  On one page from your site :
- "<foot an a half long>"
- "<generally max's out at about eight inches in captivity>"
- "<ughhh! I really wish pet stores would stop selling this beautiful fish. 2 foot long as an adult, most stunt and die prematurely in private aquaria.  This is truly a public aquarium fish at best>"
<Maximum Length is 15.7 inches or 40 cm referenced from  www.fishbase.org and "Marine Fishes" by Scott Michael.>
and http://www.wetwebmedia.com/Asohal.htm  stating this is an excellent tang for "large rough and tumble systems" (whatever that means :-)  ???
<It means don't put it in a calm peaceful community tank, it will destroy the balance of this type of system. Sohal Tangs (Acanthurus sohal) are highly territorial and will chase, chastise and occasionally kill competitors in captivity, thus a "rough and tumble system".>    
Bob seems to say a Sohal is ok in a 6' tank, others seem to say an 8' is a minimum.  
<I think bigger is better, but I would trust Bob's wisdom and experience here.>
So, bottom line, for an experienced home aquarist with top notch circulation and filtration (Tunze Tunze Tunze, large refugium, etc.) is a 180 gallon (6'x2'x2') a good home for a sohal?
<In the care of a conscientious aquarist, yes.>
Thanks...
<Welcome. -Mich>
-Andy