THE OCEAN DEEP

From the Acanthuroidei suborder, the surgeonfish is a brightly colored marine fish that is also often called the tang. There are almost seventy-five species of this incredible fish found swimming with luxurious precision among the coral reef in most tropical seas. The surgeonfish has a body that is flat with a wide oval shape. One of their most distinguishing characteristics is their amazing ability to completely change their color according to their mood. When calmly swimming about they maintain a consistent color but when a predator approaches the color pattern changes within moments. Another color pattern change occurs at night that reminds one of someone preparing for bed. This often referred to as their pajama color. In some species, such as the yellow tang, even their location affects the color pattern. For instance, when the yellow tang is found in the waters around Hawaii, they are brilliant yellows but in other locations they exhibit a brown coloration. Others, like the blue tang, exhibit a yellow coloration during the juvenile stage of their life but change to a bright blue as adults. Found in the order of Perciformes, these small fish are constantly in motion using their pectoral fins much in the manner a bird uses its wings to fly. Some have even been observed wiping their body and eyes with the pectoral fin, which is quite an amazing feat. Surgeonfish steer using the anal, caudal and flexible ends of the dorsal fin.

The surgeonfish is so named for the scalpel sharp blades that are found on their bodies. The location of these protrusions differs tremendously with the varied genera. In some surgeon fish, such as the unicorn fish, these razor like blades do not move, but appear as a bony curve that is quite poisonous. With the unicorn fish this curved blade appears like a horn of a unicorn pointing forward from the nose. There are also three oval shaped bumps on each side of the tail that can inflict a painful cut. In other species the horn is replace with a single large bump above the nose area but this is equally as sharp. In some species of the tang the well-defined blade moves quite freely when needed. As these species calmly swim the blade is tucked inside a groove on their body. But the moment they are threatened the blade comes out from the rear of the fish, point forward and ready to cut. When these surgeonfish are threatened by other species they will swim beside the intruder swinging their tails to inflict cuts. When their aim is accurate the intruder will receive long, deeply slicing cuts. When humans handle surgeonfish, extreme caution should be taken. Many an unsuspecting person has received deep wounds to their hands when attempting to remove this fish from a net or openly handle it.

In recent years the surgeonfish has become highly popular as an aquarium specimen due to their brilliant color patterns and interesting behavior. Most ocean species are algae-eaters that clean the coral reef with their teeth. Kept in an aquarium these fish seem to thrive when fed a steady diet of algae, small shrimp and mussels. One important aspect of using the surgeonfish in an aquarium is how they relate to other fish. This fish should never be kept in a small tank with other fish, even of its own species, since the constant contact caused by such a crowded space will be cause enough for this fish to view its tank mates as a threat. In the waters off Hawaii, the surgeonfish spawn between the months of December and July. Amazingly, the actual act of spawning appears to be dependent on certain lunar phases since they only spawn during a full moon. The males of most species go through a pattern coloration change as the mating time draws near. All sexually mature fish of the species come together in a large swarm, appearing to become highly agitated. Suddenly they rise quickly a few inches in the water and release their eggs or sperm, after which they return to the group below. The eggs, like those of many of the Perciformes, contain a tiny bubble of oil that causes them to rise to the surface. In just over a day they hatch and the Acronurus appear, but do not begin feeding for around five days. Once the young begin eating their diet consist mostly of the eggs of other fish and small crustaceans.

Acanthuridae ("thorn tail") is the family of surgeonfishes, tang, 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. Both the dorsal and anal 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.[1]
Most species are relatively small and have a maximum length of 15-40 cm (6-16 in), 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 whitemargin unicornfish (N. annulatus), the largest species in the family, reaching a length of up to a meter (3,3 ft). 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.
Species
• Genus Acanthurus
o Achilles tang, Acanthurus achilles Shaw, 1803.
o Whitefin surgeonfish, Acanthurus albipectoralis Allen & Ayling, 1987.
o Orange-socket surgeonfish, Acanthurus auranticavus Randall, 1956.
o Ocean surgeon, Acanthurus bahianus Castelnau, 1855.
o Black-spot surgeonfish, Acanthurus bariene Lesson, 1831.
o Ringtail surgeonfish, Acanthurus blochii Valenciennes, 1835.
o Doctorfish tang, Acanthurus chirurgus (Bloch, 1787).
o Chronixis surgeonfish, Acanthurus chronixis Randall, 1960.
o Atlantic Blue tang surgeonfish, Acanthurus coeruleus Bloch & Schneider, 1801.tfytfyt
o Eyestripe surgeonfish, Acanthurus dussumieri Valenciennes, 1835.
o Fowler's surgeonfish, Acanthurus fowleri de Beaufort, 1951.
o Black surgeonfish, Acanthurus gahhm (Forsskål, 1775).
o Finelined surgeonfish, Acanthurus grammoptilus Richardson, 1843.
o Whitespotted surgeonfish, Acanthurus guttatus Forster, 1801.
o Japan surgeonfish, Acanthurus japonicus (Schmidt, 1931).
o Palelipped surgeonfish, Acanthurus leucocheilus Herre, 1927.
o Whitebar surgeonfish, Acanthurus leucopareius (Jenkins, 1903).
o Powderblue surgeonfish, Acanthurus leucosternon Bennett, 1833.
o Lined surgeonfish, Acanthurus lineatus (Linnaeus, 1758).
o White-freckled surgeonfish, Acanthurus maculiceps] (Ahl, 1923).
o Elongate surgeonfish, Acanthurus mata (Cuvier, 1829).
o Monrovia doctorfish, Acanthurus monroviae Steindachner, 1876.
o Whitecheek surgeonfish, Acanthurus nigricans (Linnaeus, 1758).
o Epaulette surgeonfish, Acanthurus nigricauda Duncker & Mohr, 1929.
o Brown surgeonfish, Acanthurus nigrofuscus (Forsskål, 1775).
o Bluelined surgeonfish, Acanthurus nigroris Valenciennes, 1835.
o Bluelined surgeon, Acanthurus nubilus (Fowler & Bean, 1929).
o Orangespot surgeonfish, Acanthurus olivaceus Bloch & Schneider, 1801.
o Black-barred surgeonfish, Acanthurus polyzona (Bleeker, 1868).
o Chocolate surgeonfish, Acanthurus pyroferus Kittlitz, 1834.
o Gulf surgeonfish, Acanthurus randalli Briggs & Caldwell, 1957.
o Acanthurus reversus Randall & Earle, 1999.
o Sohal surgeonfish, Acanthurus sohal (Forsskål, 1775).
o Doubleband surgeonfish, Acanthurus tennentii Günther, 1861.
o Thompson's surgeonfish, Acanthurus thompsoni (Fowler, 1923).
o Convict surgeonfish, Acanthurus triostegus (Linnaeus, 1758).
o Indian Ocean mimic surgeonfish, Acanthurus tristis Randall, 1993.
o Yellowfin surgeonfish, Acanthurus xanthopterus Valenciennes, 1835.
• Genus Ctenochaetus
o Twospot surgeonfish, Ctenochaetus binotatus Randall, 1955.
o Ctenochaetus cyanocheilus Randall & Clements, 2001.
o Ctenochaetus flavicauda Fowler, 1938.
o Striped-fin surgeonfish, Ctenochaetus marginatus (Valenciennes, 1835).
o Striated surgeonfish, Ctenochaetus striatus (Quoy & Gaimard, 1825).
o Kole Tang, Ctenochaetus strigosus (Bennett, 1828).
o Tomini surgeonfish, Ctenochaetus tominiensis Randall, 1955.
o Ctenochaetus truncatus Randall & Clements, 2001.
• Genus Naso
o Whitemargin unicornfish, Naso annulatus (Quoy & Gaimard, 1825).
o Humpback unicornfish, Naso brachycentron (Valenciennes, 1835).
o Spotted unicornfish, Naso brevirostris (Cuvier, 1829).
o Naso caeruleacauda Randall, 1994.
o Gray unicornfish, Naso caesius Randall & Bell, 1992.
o Elegant unicornfish, Naso elegans (Rüppell, 1829).
o Horseface unicornfish, Naso fageni Morrow, 1954.
o Sleek unicornfish, Naso hexacanthus (Bleeker, 1855).
o Orangespine unicornfish, Naso lituratus (Forster, 1801).
o Elongate unicornfish, Naso lopezi Herre, 1927.
o Naso maculatus Randall & Struhsaker, 1981.
o Squarenose unicornfish, Naso mcdadei Johnson, 2002.
o Slender unicorn, Naso minor (Smith, 1966).
o Naso reticulatus Randall, 2001.
o Oneknife unicornfish, Naso thynnoides (Cuvier, 1829).
o Bulbnose unicornfish, Naso tonganus (Valenciennes, 1835).
o Humpnose unicornfish, Naso tuberosus Lacépède, 1801.
o Bluespine unicornfish, Naso unicornis (Forsskål, 1775).
o Bignose unicornfish, Naso vlamingii (Valenciennes, 1835).
• Genus Paracanthurus
o Palette surgeonfish, Paracanthurus hepatus (Linnaeus, 1766).
• Genus Prionurus
o Biafra doctorfish, Prionurus biafraensis (Blache & Rossignol, 1961).
o Prionurus chrysurus Randall, 2001.
o Razor surgeonfish, Prionurus laticlavius (Valenciennes, 1846).
o Yellowspotted sawtail, Prionurus maculatus (Randall & Struhsaker, 1981).
o Sixplate sawtail, Prionurus microlepidotus Lacépède, 1804.
o Yellowtail surgeonfish, Prionurus punctatus Gill, 1862.
o Scalpel sawtail, Prionurus scalprum Valenciennes, 1835.
• Genus Zebrasoma
o Red Sea sailfin tang, Zebrasoma desjardinii (Bennett, 1836).
o Yellow tang, Zebrasoma flavescens (Bennett, 1828).
o Spotted tang, Zebrasoma gemmatum (Valenciennes, 1835).
o Longnose surgeonfish, Zebrasoma rostratum (Günther, 1875).
o Twotone tang, Zebrasoma scopas (Cuvier, 1829).
o Sailfin tang, Zebrasoma veliferum (Bloch, 1795).
o Yellowtail tang, Zebrasoma xanthurum (Blyth, 1852).
Etymology and taxonomic history
The name of the family is derived from the Greek words akantha and oura, which loosely translate to "thorn" and "tail", respectively. This refers to the distinguishing characteristic of the family, the "scalpel" found each member's caudal peduncle.
In the early 1900's, the family was called Hepatidae.
In the aquarium
Tangs are very sensitive to disease in the home aquarium. However if the tang is fed enough algae and the aquarium is properly maintained disease should not be a problem. It is usually necessary to quarantine the animals using copper sulfate or formalin for a period of around 2 weeks. (Disputed, copper is lethal to fauna & inverts housed within the Acanthurus stomach. While quarrantine is a requirement, 1 month in a substrate-free holding tank matching display tank parameters is sufficient to eradicate crytocaryon irritans cysts and their offspring. Hyposalinity is a safe, effective treatment for these fish. --TheMcs (talk) 14:58, 13 April 2009 (UTC))
Adults range from 15-40cm (6-15 in.) in length and most grow quickly even in aquariums. When considering a tang for an aquarium it is important to consider the size to which these fish can grow. Larger species such as the popular regal tang (of Finding Nemo fame), Naso or lipstick tang, clown and sohal tangs can grow to 40cm (15 in.) and require swimming room and hiding places.
Many also suggest adding aggressive tangs to the aquarium last as they are territorial and may fight and possibly kill other fish.
Tangs primarily graze on macroalgae, such as caulerpa and gracilias, although they have been observed in an aquarium setting to eat meat-based fish foods. A popular technique for aquarists, is to grow macroalgae in a sump or refugium. This technique not only is economically beneficial, but serves to promote enhanced water quality through nitrate absorption. The growth of the algae can then be controlled by feeding it to the tang.