Hawaiian Bristletooth ~ Black Surgeon ~ Hawaiian surgeonfishFamily: Acanthuridae Ctenochaetus hawaiiensisPhoto © Animal-World: Courtesy Greg Rothschild
Not only is it one of the most beautiful of all the surgeonfish, the Chevron tang eats a different kind of algae than the other surgeonfish, making it one of the most desirable as well!
Called 'bristle tooth' or 'Comb tooth' tangs due to their nature of feeding. They primarily eat detritus which contains minute algae rather than the filamentous algae eaten by other tangs. The Ctenochaetus species, referred to as both the Bristletooth or Combtooth Tangs, have several rows of small flexible comb like teeth (up to 30 teeth) along with a protrusive pouting mouth. They use their teeth to lift and sift through various types of algae and detrital material off of rocks, sand, and other surfaces and use their mouths to vacuum this food in. In the aquarium you will often see little lip marks on the glass where algae used to be.
Like the others members of the Ctenochaetus genus, the Chevron Tang or Hawaiian Bristletooth has a moderate demeanor and is generally a good companion in a community tank. It can be kept with a variety of tank mates including some of the other genus' of surgeonfish. It should not be housed with aggressive fish or those with a similar body shape or diet. Its diet makes it a great complimentary companion for other peaceful surgeonfish such as the Yellow Tang or the Pacific Sailfin Tang in the Zebrasoma genus, though you need to keep an eye on compatibility.
Being among the smallest and least active of the surgeonfish, one would think a smaller aquarium would suit the Ctenochaetus. However because they need plenty of naturally growing food and accumulated detritus, cluttering a small tank with live rock to help provide for their diet reduces their necessary swimming space while under stocking live rock makes the tank too sterile and reduces their necessary food source. For long term success in keeping these fish, providing for their dietary needs is of primary importance. To meet their dietary needs they will need a large aquarium with lots of live rock. They will benefit even more with the inclusion of live sand. The live rock and live sand along with surfaces of the aquarium glass will provide a lot of areas for good algae growth and detritus build up to help accommodate this constant feeder.
For more Information on keeping marine fish see:
Guide to a Happy, Healthy Marine Aquarium
Habitat: Natural geographic location: The Chevron Tang or Hawaiian Bristletooth was described by Randall in 1955. They are found in the Central Pacific (the Pacific Plate) from the Hawaiian Islands to Palau and south to Samoa and Marquesas Islands. In their natural habitat they are found at depths between 16 to 131 feet (5 - 40 meters). Adult are seen in small groups in the shallower highly oxygenated surge areas among crevice ridden rocks and boulders, while juveniles are solitary in more coral rich areas.
Description: The Chevron Tang is very beautiful and striking as a juvenile. It has a bright orange colored body and head with variegated bright blue lines, radiating in somewhat of a herringbone type pattern. The fins are violet tinged becoming bright blue posteriorly, just above and below the caudal peduncle.
The adult has a dark orangish red coloration overall with multiple thin dark green-blue lines. When seen from a distance the adult appears a uniform black and are known as the Black Surgeon in Hawaii. Only up close can you see the lined color patterning.
On each side of the caudal peduncle is a single spine or "scalpel" used for defense or dominance. When not in use the spine is folded down into a groove. This single spine is what places the Ctenochaetus genus in the subfamily Ancanturinae, along with the other single spine genera Acanthurus, Zebrasoma, and Paracanthurus. Though unlike these others, the spine on the Ctenochaetus is quite small. Even so, caution needs to be exercised when handling surgeonfish as a cut from its scalpel can cause discoloration and swelling of the skin with a high risk of infection. The pain lasts for hours then still ends up having a dull ache.
Unlike most of the other tangs of the Acanthuridae family who posses 9 dorsal spines, the Ctenochaetus have only 8 dorsal spines (the first one being very small). The Ctenochaetus species are often referred to as the Bristletooth or Combtooth Tangs, due to their nature of feeding. They have several rows of small flexible comb like teeth (up to 30 teeth) along with a protrusive pouting mouth. These teeth are adapted for lifting and sifting various types of algae and detrital material off of rocks, sand, and other surfaces and then they use their mouth to suck the food up. In the aquarium you will often see little lip marks on the glass where algae used to be from this feeding behavior.
Maintenance difficulty: Bristletooth or Combtooth Tangs are generally considered more difficult to keep, but with some knowledge of what to look for when obtaining a specimen and by providing for its needs, you can have a successful experience. Some guidelines for selecting a healthy fish include avoiding those with damaged fins and more importantly those with a damaged mouth. Also be sure the fish is eating. If it grazes on the rockwork and the sand of the aquarium it can be a good specimen, and also if it accepts prepared foods.
This fish needs a lot of water movement creating an oxygen rich environment rather than a placid aquarium. Being quite agile, it needs plenty of swimming space along with corals/ rocks to provide crevices for retreat and sleeping at night. It will do best in an environment that provides consistency, not only in water conditions and quality, but also in decor and fellow inhabitants. It can be housed in a community reef environment as it will not harm corals or invertebrates. Live rock and live sand will lend themselves to natural algae growth and detritus build up which this fish will enjoy grazing on, and makes it a valuable addition to a reef environment.
Surgeonfish and tangs are continuous feeders and they need to be provided a proper diet. They are susceptible to nutritional disorders which may cause color loss and LLD (lateral line disease). Supplementing their diet with the addition of vitamin C to their food or adding a vitamin supplement directly to their water can help to avoid or aid in reducing these ailments. They are also susceptible to bacteria resulting from organic buildup which deteriorates water quality. Consequently they will need vigorous filtration, protein skimming, and regular small water changes.
Many of the Acanthuridae members are very colorful, active, and attractive to aquarists. But they do not produce as much skin mucus on their bodies as other fish and can be susceptible to diseases such as Marine Ich and Marine Velvet. Surgeonfish are definitely a candidate for quarantine when you first receive them. They can be treated successfully with medical care or copper drugs, but because they have an important microfauna in their digestive system, prolonged or continuous use of a copper treatment is not advisable.
In the wild a cleaner wrasse (Labroides sp.) will help them by taking parasites from their bodies, however these wrasses are extremely difficult to sustain in captivity. Alternative fish such as Neon Gobies (Gobiosoma spp.) or cleaner shrimp can help them by providing this cleaning service in the home aquarium.
Diseases that Surgeonfish and Tangs are susceptible to:
Marine Ich (white spot disease), Marine Velvet and Lateral Line Erosion (LLE)
Foods: Though the Chevron Tangs are considered herbivores, in the wild they feed on detritus, a thin film on the substrate containing many nutrients including dinoflagellates (minute marine protozoans), diatoms (unicellular algae), and large amounts of other organic material. In the aquarium a large portion of their diet will be obtained from grazing on the naturally growing minute algae and the detritus. However this food source will not be sufficient to maintain them, so they must also be offered supplemental foods.
The majority of their intake will be vegetable matter but they do need some meaty foods as well. Provide lots of marine algae, prepared frozen formulas containing algae or spirulina, frozen brine and mysid shrimp, and flake foods. Japanese Nori or other seaweed can be adhered to the aquarium glass with a vegetable clip. Feed 3 times a day in smaller amounts instead of a large quantity once a day. As continuous grazers, they will benefit from this and it will also keep the water quality higher over a longer period of time.
Providing a vitamin supplement (including vitamin C) can help provide for their nutritional needs, and vitamin C can help prevent or reduce Lateral Line Erosion (LLE). This can be done by soaking dried pellets with liquid vitamins, adding vitamins to the food, or adding a liquid vitamin into the water. It is also said that pellets soaked in garlic may help fend off Marine Ich. Some hobbyists also report success with supplemental foods such as previously boiled or frozen zucchini, broccoli, spinach, and leaf lettuce.
Maintenance: An agile swimmer and constant grazer it will spend a good deal of its time picking at the rock and sand as well as the aquarium glass, removing algae and detritus. Frequent water changes are not necessary, rather normal water changes at 10% biweekly or 20% monthly are fine.
For more information see, Marine Aquarium Basics: Maintenance
These fish need a lot of water movement creating an oxygen rich environment rather than a placid aquarium. They are also quite agile and need plenty of swimming space along with corals/ rocks to provide crevices for retreat and sleeping at night. They will need a large aquarium with lots of live rock. They will benefit even more with the inclusion of live sand. Live rock and live sand will lend itself to a lot of good algae growth and detritus build up to help accommodate this constant feeder, which makes these fish a valuable addition to a reef environment.
Minimum Tank Length/Size:
A minimum 75 gallon (284 liters).
Light: Recommended light levels
It nature it is found in sunlit areas. It can be kept under normal lighting conditions in the aquarium, but can also be kept under very bright light as long as some dimly lit spaces are provided.
This species lives in tropical areas. Temperatures between 73 -80° F (23 - 27° C) will serve them well.
Water Movement: Weak, Moderate, Strong
All surgeonfish and tangs thrive with good water movement, need lots of oxygen, and love to have the water rushing over their gills at times. Provide strong movement in at least one area of the tank.
Water Region: Top, Middle, Bottom
It will spend time primarily in the middle and bottom of the aquarium, picking at the rock and sand as well as the aquarium glass. It will sleep in crevices at night.
Social Behaviors: The great thing about the Chevron Tang is that they are fine in a reef setting with inverts and corals, and they will graze on the algae. This is one of the more peaceful surgeonfish. Its moderate behavior makes it a good companion in a community tank.
It should not be housed with aggressive species but rather more peaceful fish. Avoid fish of a similar body shape and those that eat the same natural diet. In the wild adults maintain pair bonds, however as it is almost impossible to sex these fish they are best kept singly unless they are a proven mated pair. It can be kept with a variety of other tank mates including some of the other genus' of surgeonfish. The peaceful sailfin tangs of the Zebrasoma genus can be a good choice as they eat a different kind of algae, so these two tend to compliment each other. If it is be kept with any tangs, add this fish first and let it get established before adding another tang. Always watch for compatibility as the Indian Gold Ring can be a target for aggressive tank mates and become stressed.
Surgeonfish and tangs can be territorial, sometimes just with their own kind and sometimes with other species. Introducing a new surgeonfish into an aquarium that already houses one or more is usually a problem. It is best to initially introduce several species together rather than adding a new one later on. Though a large aquarium can help alleviate many problems, be aware of the social behaviors of any species you are considering to prevent compatibility problems.
Breeding/Reproduction: Some species of surgeonfish have spawned in public aquariums and there have been a few scattered reports of spawning in home aquariums, but regular spawning and the rearing of the young has not yet been reported.
Though the Chevron Tang has not yet been bred in captivity, this species has been observed performing pair spawning in the ocean. Adults maintain bonded pairs in the wild. The only species from the Ctenochaetus genus that does not bond is the Yellow-eyed or Kole Tang C. strigosus, though they too will spawn in pairs.
For information on breeding and the development of the fry, see: Marine Fish Breeding: Tangs.
Photo courtesy: John Rice
Availability: The Chevron Tang or Hawaiian Bristletooth is often available at retailers as well as on the internet, though they are rather expensive. They are priced starting at around $150.00 USD and up.