Originally Posted by
1boatnut
http:///forum/post/2478118
I find one of the biggest problems here is nobody wants to accept that many of us will grow in this hobby.People jump all over Tangs being kept in 75 gal tanks,even after some state they are up-grading. A 2" Tang in a 55 gal is fine for a period,but most here wont accept that. I have a Tang that has NO WAY doubled in size in the last 7 months.
I can make a blanket statement that no Tangs should be kept in a tank less than 7',and then argue with nothing more than me saying my fish was in a 6' and is now much happier in the 7'.
The truth be told,certain Tangs should be left where mother nature put them,but we as humans will always find a way to rationalize ways for us to keep them.
There is definitely a point in there that many of the anti-tang-police brigade uses, where if we say a 6' tank should be a minimum, what's to say we shouldn't be recommending a 7' tank. To that I would definitely counter that "bigger is always better", especially for the more sensitive ones (like the Achilles) where water quality is a big factor into their survival.
Now, I've noted several times on threads that a tang in a 55g will work for up to a year if that tang is a juvenile. In fact, IMO, it's probably better for the tang if it's in a tank where it's not pacing half the tank to try and fight for food, especially if it's staking out territory on the other side of a 6' tank from the veggie clip. I do, however, think that often times people get something in a small tank rationalizing that they're going to upgrade and then never do. I am, my hippo lived in a 55g for 7 months and will be going into a 180 as soon as it's done cycling, but it's taken a lot of work/time/money to get to this point and I had often considered giving up the upgrade. The driving force, however, is the well-being of my fish and the fact that I personally want to keep more tangs that I know won't live in my 55g.
With my hippo I've seen it all; ich twice (still in treatment for the second bout), HLLE brought on by stress of that treatment, which then didn't heal because of living in the 55g with 2 clowns that are bigger than she is, and even at 1.5" she still paces back and forth seemingly looking for more room to swim. She'll often swim into the powerhead stream just to get a good work-out. Many times, you'll hear, juvenile tangs will not survive this long and with this much trouble. I'm lucky that somehow she is still alive (or perhaps is the time I've devoted to making sure that she stays that way), but there are many factors that play into the mortality rate of juvenile tangs. Several arguments here have been that there are multiple factors in keeping these fish healthy in a smaller environment, but the flip side is that there are several factors that could be implicated in their demise as well... especially when starting with a juvenile.
So more to the general issue; I emailed Bob Fenner because there were some interesting notations to the tank size issue on the website he posts on usually. The Acanthurus, Ctenochaetus, and Zebrasoma families all note a guideline size starting at 50 gallons so I asked if this was outdated and if there was anything more current he could offer to help the debate. He believes that some of the Acanthurus, and most of the Ctenochaetus and Zebrasoma will do fine in a 50g volume tank that is not crowded, has good maintenance, and adequate nutrition. However many Acanthurus tangs will grow to be rather large and cannot be kept in this environment. Conversely, anything in the Naso and Prionurus families needs hundreds of gallons (which in my mind translates to at least 200+ gallons). Paracanthurus (blue hippo) should be in something 75g or larger. Also, I did ask for any data that could relate to the issue and he noted that most data on the subject are from much, much larger systems (I'm assuming he meant public aquariums where reef tanks are in the thousands of gallons range) and that most of the information that points to the 6' "rule" is more or less anecdotal.
There is also something very enlightening in his book "The Contentious Marine Aquarist" that I re-read last night in the Tangs section: tangs need a high level of dissolved oxygen otherwise they will be stressed. I'm personally taking this to mean that if you keep glass tops on your tank, or have low gas exchange for any reason, this could be a source of stress for tangs. There were a few other points that I would like to quote but I didn't get a chance to post last night, and I left the book at home when I came to work... so I'll post them later.
At any rate, I'm trying to find more data to support one side or the other, but as muggiwhplar noted, there is likely a general lack of real studies into the subject since this is a hobby. I'll also post back once I get info from my LFS's MBs on their tank size recommendations.
