The Naso Tang (Full Article)Author: Mark Denaro
The naso, or lipstick, tang (Naso lituratus) has been popular with marine aquarists since the beginning days of marine fish exportation from the Philippines. N. lituratus is an excellent ambassador for what may well be the most peaceful genus of surgeonfish. The Naso species are all large, herbivorous, gregarious, outgoing fish, and all the available species are popular with hobbyists. Naso species range across the tropical Indian and Pacific oceans, but most species are seldom collected for the home aquarium. The species that are imported for the aquarium trade have all proven hardy in the aquarium as long as their needs are met.
Housing Naso Tangs
The genus Naso is diverse, and many of the species grow to lengths of 2 to 3 feet, making them suitable only for extremely large tanks in public aquariums. There are four species that are imported regularly for sale to home hobbyists. They all grow to significant sizes and should be housed only in the largest of home aquariums, but we all know the reality is that many of these specimens are housed in tanks they will eventually outgrow by hobbyists who think they’ll have a larger tank for them by the time they “need” it.
A little confession is in order here. I bought my first Naso tang in about 1978 and housed it in a 20-gallon long that it shared with a long-tentacle anemone, an urchin, and eventually a panther grouper. Obviously, this was not an ideal situation. Nonetheless, the fish grew from 3 to 6 inches in that tank before eventually succumbing to a pH crash. By that time, the anemone and urchin had been removed, but the undergravel filter and air-driven protein skimmer just couldn’t keep up with the load produced by the two 6-inch fish even with 25 percent weekly water changes. The grouper survived and was moved to a 30-gallon tank, but it was soon apparent that even that was too small for him, resulting in my trading him back to the shop where he was purchased. After another 33 years in the hobby, would I ever consider adding a Naso of any species to a 20-gallon aquarium? Absolutely not, and you shouldn’t either. The bare minimum tank, even for a small Naso, is probably 75 gallons, but in an ideal situation, these species should be kept in tanks of at least 200 gallons, with even larger tanks being much preferred.
Nasos tend to be active in all levels of the aquarium, so they are excellent additions to taller tanks. Indeed, if you have the ability to put one in a large tank that is 4 or more feet in height, a naso (or a small school of nasos, if the tank is large enough) makes a wonderful addition because it will provide movement in the upper half of the tank. This is unlike most other reef fishes, which are more bottom-oriented. Deep tanks can present some real challenges with dissolved oxygen levels, so if you do opt for a tall tank, be sure that you have some pumps near the substrate that circulate water from the bottom to the top. This will help maintain a consistently high level of dissolved oxygen throughout the tank by not allowing any stratification to develop, which would otherwise result in lower dissolved oxygen levels near the bottom.
Feeding Naso Tangs
Naso tangs are primarily herbivores by nature, though they also feed on plankton. All Naso species should be offered a varied diet consisting primarily of algae or vegetable-based foods with as wide a variety of meatier fare as possible mixed in. Any of the typically available frozen foods, such as mysis, brine shrimp, krill, squid, mussels, shrimp, etc., are good inclusions. The carotenes in foods such as mysis, brine shrimp, and krill can help enhance the orange and yellow colors prevalent in some species. Algae and seaweed formulas should constitute the bulk of the diet and can be offered in frozen or dried forms, with flakes and pellets being readily accepted. Sheets of nori and other seaweeds are eagerly eaten, as are terrestrial plant materials, such as romaine lettuce, bok choy, spinach, and broccoli.
In terms of diet and behavior, the Naso species are good choices for reef aquariums. They will nibble at any green algae growth in the system and will not bother any sessile invertebrates. The problem with adding them to reefs, though, is the amount of waste they produce. Small specimens in large reef tanks can work well. Larger fish can also be kept successfully if the reef is filtered in a manner that allows the waste to be dealt with efficiently. In addition to algae and plankton, N. lituratus has been known to eat young bristleworms, so its addition to a reef can be beneficial in helping keep their population in check.
Filtering a Naso Aquarium
Because we’re dealing with herbivorous fish that grow large, copious amounts of waste will be produced, so it is extremely important that filtration be as efficient as possible. Indeed, filters should be oversized for tanks housing these fish. Consider them to be the vegetarian equivalent of messy carnivores like groupers, and filter their tanks accordingly.
A characteristic that sets the genus Naso apart from most other tangs is the presence of multiple spines on the caudal peduncle. Tangs of other genera, such as Acanthurus and Zebrasoma, possess a single spine (or scalpel, if you prefer surgeonfish to tang as a popular name). The spines in Naso species are large and fixed in an open position, not retractable like those in Acanthurus and Zebrasoma. The spines grow as the fish grows and are substantial on adults. This can cause some issues in the aquarium.
As the fish swim along the tank walls, the spines will rub on the glass or acrylic and can scratch it. This can become a real problem over time, as the tank will become more and more scratched. In general, I’m an acrylic guy and really prefer acrylic especially for large tanks, but it is important to be sure that you purchase an aquarium-manufactured cell-cast acrylic, which is much more scratch resistant than lesser-quality acrylics. That said, acrylic will still scratch a bit more easily than glass, but one of the biggest advantages of acrylic over glass is the ability to buff out the scratches. Buffing out scratches is easier when the tank is manufactured with higher-quality acrylic. There is a misconception that acrylic tanks need to be drained in order to buff out scratches, but this is not true. The scratch removal kits currently on the market require the surface to be wet and involve no chemicals, so they can be used on operating tanks without any need to drain the tank or remove its inhabitants. Scratches in glass, on the other hand, are permanent.
Purchasing Naso Tangs
Carefully observe any fish whose purchase you are considering. The fish should be active and breathing normally. The fins should be raised and lowered in accordance with its activity in the tank. Look very carefully at the body to be sure it is well filled out. A slightly pinched belly is okay and just indicates that the fish hasn’t been fed in a few days, but the back should be well rounded. If the back appears thin, the fish has gone too long without eating and is not in good condition, as it has begun to metabolize its own musculature as a source of nourishment.
Ideally, you should see the fish eat, but if that is not possible, it shouldn’t be a deal breaker with the Naso species, as I’ve never seen one that didn’t start feeding. Large specimens may take a few days or even up to a couple of weeks to start feeding in captivity, but they always start. Adult specimens of all marine fish are not as adaptable as their juvenile brethren, but age does not pose a significant issue in the acclimation of any of the Naso species, so if you have a very large aquarium and want to acquire a show-sized specimen or an adult male N. lituratus or N. elegans with the lyre extensions to the tail, don’t hesitate to do so.
Naso lituratus, the naso or lipstick tang, or sometimes the smooth-head unicornfish, is the most readily available and popular species in the genus. The head shape is decidedly equine. If the common name seahorse weren’t already in use, it could be applied to this species. It is collected for the aquarium trade in Hawaii, the Philippines, and the islands of Indonesia that are in the Pacific Ocean.
Most of the individuals that reach the hobbyist are between 3 and 6 inches in length, though this species can reach a length of 18 inches. The colors deepen and intensify as the fish age, so young specimens may have a body color that can best be described as gray while older individuals will develop a deep chestnut-brown body color. The nighttime coloration features a series of white spots, so don’t be alarmed if the fish looks different the morning after you’ve purchased it. The lips are orange, leading to the common name of lipstick tang. The snout is dark brown to black and there is mustard yellow around the eyes and in a line down to the mouth. The chest is yellow in older specimens. The dorsal is mostly black with a blue line along the back just below the dorsal.
Adult males develop lyre-shaped extensions from the top and bottom lobes of the caudal fin, technically described as an emarginated fin with trailing filaments. N. lituratus are extremely hardy and suitable for aquarists of all experience levels. Lipstick tangs collected in Hawaii tend to be a bit larger than those from other areas and are in better condition on arrival. They are more expensive but well worth the extra cost.
The blonde naso (N. elegans) replaces N. lituratus in the Indian Ocean and Red Sea. The two species are almost identical in size, shape, and habits. The easiest way to distinguish them is to look at the dorsal fin, which is yellow in N. elegans and mostly black in N. lituratus. When N. elegans was first imported in significant numbers in the late 1980s and early 1990s, it was frequently referred to as the Madonna tang in reference to its dorsal fin being similar to the color of Madonna’s newly blonde hair. That common name didn’t stick, however.
Vlamingi’s tang (N. vlamingii) is also referred to as the big nose tang or the big nose unicornfish. This species can grow to a larger size than the previous two species, reaching 2 feet in length. It is extremely widespread, ranging from the tropical South Pacific west to the eastern coast of Africa. Once very rare in the hobby and very expensive, it is now available with some regularity and exported from numerous locations. Consequently, the price has come down considerably so that it is within the range of most marine hobbyists. Juveniles are frequently misidentified and sold as N. lopezi. The true N. lopezi is only very rarely collected for the trade.
The unicorn tang (N. unicornis) also roams a very wide range, extending from Hawaii west to east Africa and the Red Sea and from southern Japan south to Australia. N. unicornis grows to 28 inches in length. Juveniles have a smooth forehead, but as the fish grow, they develop a horn that projects straight forward from the forehead. The horn is more developed in adult males, though it seldom extends beyond the mouth. Unicorn tangs are rather drab in coloration, being a uniform grey, but the horn is so striking that it more than makes up for the lack of bright colors. Adult specimens are suitable only for the very largest aquariums.
Other species may be available from time to time, but be sure to research them prior to purchase, as many grow even larger than those discussed here. If you can provide adequate space, all the Naso tangs make active, attractive, and long-lived additions to your marine collection.
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