What tang for my 30G?

[SAT]

The moderators and staff of Reef Central are tired of squabbles about whether it's OK to put a tang in a small tank or whether it's OK to have multiple tangs in any tank. As a reminder:

Here at Reef Central, we believe that dialogs between participants should be conducted in a friendly and helpful manner. If you disagree with a posting, please express yourself in a way that is conducive to further constructive dialog. Conversely, when you post on any given subject, you must be willing to accept constructive criticism without posting a hostile or inflammatory response. Personal attacks of any kind will not be tolerated. Please let’s work to insure that Reef Central remains a friendly and flame free site where everyone, especially newcomers, can feel free to post questions without fear of being unfairly criticized. Thank you for your cooperation.

If you think someone is getting out of line, please report the post to the moderators. Do not attempt to take matters into your own hands.

For newcomers we offer the following advice. This is not intended to be the last word in tang keeping, but we suggest you should challenge this advice only if you have a good basis for doing so:

1. Tangs are not good choices for newly set up aquaria. To thrive they need a stable environment with pristine water conditions. Anyone thinking their newly set up aquarium is stable is invited to read through the following thread:
Maturity Issues

2. Tangs are medium to large, active fish that need plenty of space. On the question of tank sizes, we defer to Scott W. Michael, who recommends the following minimum sizes in Marine Fishes, 500+ Essential-To-Know Aquarium Species, Microcosm Ltd., 1999:[list=a][*]Acanthurus achilles, Achilles Surgeonfish, 100 gal (380l).[*]Acanthurus coeruleus, Atlantic Blue Tang, 75 gal (285l).[*]Acanthurus japonicus, Powder Brown Tang, 75 gal (285l).[*]Acanthurus leucosternon, Powder Blue Tang, 100 gal (380l).[*]Acanthurus lineatus, Lined or Clown Surgeonfish, 180 gal (680l).[*]Acanthurus nigricans, Whitecheek Surgeonfish, 75 gal (285l).[*]Acanthurus olivaceus, Orangeshoulder Surgeonfish, 135 gal (510l).[*]Acanthurus pyroferus, Mimic Surgeonfish, 75 gal (285l).[*]Acanthurus sohal, Sohal Surgeonfish, 180 gal (680l).[*]Acanthurus tristegus, Convict Surgeonfish, 75 gal (285l).[*]Acanthurus tristis, Indian Mimic Surgeonfish, 75 gal (285l).[*]Ctenochaetus hawaiiensis, Chevron Tang, 100 gal (380l).[*]Ctenochaetus strigosus, Kole's Tang, 75 gal (285l).[*]Naso brevirostris, Spotted Unicornfish, 180 gal (685l).[*]Naso lituratus, Orangespine Unicornfish or Naso Tang, 135 gal (510l).[*]Naso unicornis, Bluespine Unicornfish, 200 gal (760l).[*]Paracanthurus hepatus, Pacific Blue Tang, 100 gal (380l).[*]Zebrasoma desjardinii, Indian Ocean or Red Sea Sailfin Tang, 135 gal (510l).[*]Zebrasoma flavescens, Yellow Tang, 75 gal (285l).[*]Zebrasoma scopas, Brown Tang, 75 gal (285l).[*]Zebrasoma veliferum, Sailfin Tang, 135 gal (510l).[*]Zebrasoma xanthurum, Purple Tang, 100 gal (380l).[/list=a]
You will note that none of these minimum sizes are less than 75 gallons. If you have a tang in a smaller tank, you should expect that some people will give you a hard time about it. Expressing outrage about that could result in suspension of your posting privileges. We are not, BTW, giving a free pass to the self-styled "Tang Police" to be abusive.

3. The above sizes assume a standard rectangular shape with plenty of open swimming space. If your tank is full to the brim with coral, your tang won't be happy. Tanks 125G or larger are assumed to be at least six feet long (approx. two meters). Where possible, choose longer rather than deeper shapes. While smaller species may be OK in a four foot tank, they will probably do better in a five foot or longer tank.

4. We do not condone the practice of keeping more than one specimen of the same or very similar species together in the same aquarium, except possibly for Zebrasoma species in a very large tank.

5. If you wish to keep multiple dissimilar tangs in the same aquarium, we recommend you have an aquarium significantly larger than the sizes listed above.

If you are an experienced aquarist with something constructive to add, please feel free to comment on this topic. However, stating an inflamatory opinion just to get a reaction is considered a violation of the RC User Agreement.