Tangs and Surgeonfish

[snorvich]

Tangs & Surgeons

Acanthuridae ("thorn tail") is the family of surgeonfishes, tangs, and unicornfishes. The family includes about 80 species in six genera, all of which are marine fish living in tropical seas, usually around coral reefs. Many of the species are brightly colored and popular for aquaria.

The distinctive characteristic of the family is the spines, one or more on either side of the tail, which are dangerously sharp. The dorsal, anal and caudal fins are large, extending for most of the length of the body. The small mouths have a single row of teeth used for grazing on algae.

Surgeonfishes sometimes feed as solitary individuals, but they also often travel and feed in groups. It has been suggested that feeding in groups is a mechanism for overwhelming the highly aggressive defense responses of small territorial damselfishes that vigorously guard small patches of algae on coral reefs.

Most species are relatively small and reach a maximum length of 6–16 inches, but some members of the genus Acanthurus, some members of the genus Prionurus, and most members of the genus Naso can grow larger, with the white margin unicornfish (Naso annulatus), the largest species in the family, reaching a length of up to three feet. These fishes can grow quickly in aquariums so it is advisable to check the average growth size and suitability before adding to a marine aquarium. Reef Central has a sticky denoting the recommended tank size for various species.

Tangs are commonly referred to as Surgeonfish or Doctorfish, because of the sharp blades on their tail. If appropriately sized to the tank size, they make a wonderful addition to the reef or fish only aquarium. If more than one species of Tang fish or surgeonfish is going to be kept, introduce different genera along with different sized specimens simultaneously to limit aggression. We are going to characterize these fish in groups:

Naso tangs including Naso unicornis, Naso vlamingii, Naso lituratus, and Naso elegans tend to be gentler fish that get very large and require very large (long) aquaria.

Ctenochaetus tangs are more moderately sized tangs but can be very aggressive towards conspecifics; this group can be housed in 75 gallon aquaria or larger

Super aggressive tangs such as Sohal tang and Clown tang can be aggressive towards other tangs as well as any other fish. Keeping this group of tangs is for experts only due to their hyper aggressive nature.

Generally tangs will dislike other tangs so great care must be used in trying to keep them together in any but very large tanks. When trying to maintain multiple tangs in larger aquaria, it is ideal to try and keep different genera together, and introduce them simultaneously to the display.

Although Tangs will eat meaty foods along with the other fish in the aquarium, it is important that they are offered plenty of marine based seaweed and algae. This will strengthen their immune system, reduce aggression and improve their overall health. Offer dried seaweed such as unflavored Nori tied to a rock or use a veggie clip, and feed at least 3 times per week.

Q.: What tang will fit in my 30gal?
A.: None. Read the recommended tank size for tangs at the top of the reef fish forum.

Q.: What tang will fit in my 65gal?
A.: None. Tangs, while unfortunately ubiquitous in the hobby, have very special needs that most who buy them aren't prepared to meet. Most of all, tangs require large tanks, of which a 65 is most certainly not.

Q.: What is a large tank?
A.: Larger than many new to the hobby think. No tang belongs in a tank shorter than 4ft and/or less than 75gal. When dealing with tangs, a large tank is at least 6ft long and over 150gal.

Q.: I have a 4ft tank, can I get a tang.
A.: Yes, but choose only from the list of smaller tangs.

Q.: What are the smaller tangs?
A.: Tangs of the genus Ctenochaetus (the bristletooth tangs), the yellow tang, and the convict tang. All other tangs will require a 6ft tank or longer.

Q.: Will keeping a tang in a small tank stunt its growth?
A.: No. Tangs aren't goldfish -- they don't stunt. While they generally grow to smaller sizes in captivity than in the wild, the difference is small. Remember that tangs will eat constantly in the wild and most aquarists cannot accommodate that need. That is one reason why larger tanks are required.

Q.: A LFS or online vendor says that a tang will be fine in a smaller sized tank than you say.
A.: People here at RC have nothing to sell you but your LFS does. Many literature sources are outdated, still using preliminary husbandry data from before the hobby fully evolved. Other literature sources are for keeping an animal in a completely bare tank with no obstructions, for perhaps scientific or research purposes. Tank size data for tangs presented here has come from years and years of accumulated experience from hundreds of fish keepers.

Q.: What will happen if I put my tang in a tank too small?
A.: When he or she outgrows it, lots of problems: Stress, disease, aggression, and destructive behavior are the most commonly reported.

Q.: Do tangs grow fast?
A.: Yes, but usually the larger ones grow the fastest.

Q.: I want to get a juvenile for my small tank and I'm upgrading later. Should I?
A.: No. Stock for the tank you have, not the tank you may someday probably possibly maybe have. Life can be unexpected, and we are talking about fish with life spans over 10 years.

Q.: Why can't I just give the tang away when it gets bigger?
A.: Who are you going to give it to? Most public aquariums will absolutely not accept donations from hobbyists. Also, think about what you are doing. Cute juveniles are taken from the wild and brought into the hobby because there is a demand for them. When you buy that fish, you are telling the supplier to keep collecting more cute juveniles. Part of that demand is from hobbyists who are unprepared to keep the animal for its natural life. As previously noted, tangs require tanks much larger than many novices are used to. Many hobbyists simply do not have tanks big enough to house adult tangs. Finding a home for an adult tang can be very difficult. So what you have done is provided the demand to encourage collecting more juveniles, and then dumped a large, adult fish back into the market for which there may be little secondhand demand.

Q.: What is this about length being more important than volume?
A.: Tangs are active swimmers. That is why they do so poorly in a small tank. They need to be able to swim for some length before turning around. So to a certain extent, length is more important than volume. Length is measured as the longest glass pane to the aquarium.

Q.: What is this about Naso tangs getting large?
A.: Naso is the name for the genus of larger Surgeonfishes, and of which there are 19 identified species. The common name “Naso tang” usually refers to (Naso lituratus) or the Blonde Naso Tang with the yellow dorsal fin (Naso elegans). All tangs of the genus Naso grow very large, and ultimately require 8ft tanks when full grown. Except for the common Naso tangs (Naso lituratus and Naso elegans), which is the smallest, leave the rest (like the Vlamingi, (Naso vlamingi) in the ocean where they belong, unless you have a sufficiently large system (over 8ft).

Q.: Can I get an Achilles tang?
A.: Probably not. Achilles tangs are very sensitive fish with special needs. Read the Achilles tang primer first.

Q.: Should I get a clown tang?
A.: No. That is, not unless you have a very large tank, 8ft long or bigger, and all aggressive tank mates. Clown tangs are offered as cute little juveniles. These fish are known for their large adult size and aggression, and as such, are best left in the ocean.

Q.: Should I quarantine my tang?
A.: Absolutely.

Q.: Are all tangs susceptible to ich?
A.: Yes, very much so. That is why quarantining first and then treating as necessary is extremely important.

Q.: What should I feed my tang?
A.: Tangs are herbivores. Some are more planktonovorous than others, but all require some vegetable matter in their diet. Be sure to provide them with ample green food daily. Appropriate green food is dried seaweed (nori), available at your LFS, and more nutritional vegetables that have been blanched.

Q.: Are you kidding, my tangs are perfectly happy.
A.: They seem fine to you. That doesn't mean they are. Like all wild creatures, tangs do not show weakness until they can physically no longer hide it. On the reef, weakness singles you out for predation. Therefore, a fish may be quietly suffering without you knowing. It takes a trained eye to be able to determine if a fish is stressed or unhappy in its environment.

Q.: Why are there so many FAQs about tangs?
A.: Tangs are probably the most abused fish in the hobby. Many novice aquarists are drawn to tangs, and understandably so. They are large, bright, colorful, active swimmers. The problem is: tangs have very special needs that the novice aquarist is either unprepared for or unwilling to meet, and that is where the problems begin. Perform a search in the forum for "tang" and "problem". Tangs are definitely big boy fish, and as the saying goes: don't keep big boy fish in school boy tanks. In reef keeping, the tank is one of the most inexpensive pieces of equipment. So why not just get your fish the tank it needs?
_

[Virtuoso]

snorvich, thank you for the very informative post. I agree with you that many new people to the hobby are attracted to tangs. One of the first tanks that I saw that started to get me into the hobby was a 30g with a yellow tang in it. This was set up by an older lady and she did not do a whole lot of research on the internet.

When I decided to start up my tank I purposefully went a little larger than I was comfortable with, a 90g. And while I have not stocked it yet I am glad that I did. I would like to put a tang in there, and was leaning toward a "Brown Tang" / "Scopas Tang". The tang sticky at the top of the forum lists them as a 75g minimum, but I have seen some people hint that that is not big enough. LiveAquaria also lists them as needing 125g. What do you think?

[snorvich]

A tenochaetus tang would work but do not think about putting another tang in your sized tank.

[Virtuoso]

Absolutely not. Would be the only one. Thank you for the straight answer.

[redsoxfan692]

Great writeup

Soaking up all of this info like a sponge (is there a pun there?)

This is sort of like a tank I saw for sale somewhere on craigslist.. it was a 55 gal tank with two gigantic oscars and a large pleco. I just shook my head.

Anyway, thanks for the writeup!

[Sk8r]

THanks, Snorvich.

It's really useful for people to know a) how very FAST marine critters grow [seagoing puppies become large mastiff dogs in an amazingly short year or so] and b) even if a fish is surviving, it will start taking out its tankmates or going nuttier than the bubble-worshipping tang in Finding Nemo. Unfortunately, what the writer of that screenplay meant to demonstrate was the Worst Tank In The World, with a tang gone bonkers, several inappropriate species in too small a tank, and Our Heroes, capping the lot---and what the public-at-large, including impressionable children, retains in their heads is, "Oh, that's what I want my tank to look like!" Don't be Those People. Fix it in your head as What NOT To Do! And if you're a parent, explain that it was a Very Bad Tank and that little Nemo needs a whole lot more than That Tank.

[Angel*Fish]

Very well done, Steve. I've never seen such an excellent article on tangs. Very nice.

[snorvich]

thanks. Actually this is the first of many. Written by myself and reviewed by Kevin Kohen of Drs. Foster and Smith, the collection will be a sticky which gives general care and compatibility.