Yellow-eyed Tang ~ Kole Tang
A favorite for reef aquariums, the Yellow-eyed Kole Tang eats different algaes than other surgeonfish and has a subtle beauty all it's own!
The Yellow-eyed Kole Tang juvenile starts out all yellow. Adults are reddish brown with very thin, pale blue, horizontal lines that run the length of the fish. The face has small pale blue spots and the eye is surrounded in a bright yellow circle! Their mouth is purplish blue and their pelvic and pectoral fins are brown. Their dorsal and anal fins are edged in bright blue and the fins also have the same very thin, pale blue lines at the base, but then the lines shoot backwards towards the tail fin. The Yellow-eyed Kole Tang male grows up to 7.1" (17 cm), however they grow up to a little over 5.5" in the first 4 years, and then much slower after that. Females are smaller and this genus only lives for 35 years. (Choat and Axe, 1996). They are best kept by intermediate aquarists.
The Ctenochaetus genus is referred to as both the Bristletooth or Combtooth Tangs. What separates this genus is their multiple rows of small, flexible comb like teeth (up to 30 teeth) that they use to whisk (or comb) the sand and rocks, then use suction to draw in various types of algae and detrital material. They primarily eat detritus which contains minute algae, rather than the filamentous algae eaten by other tangs, making them a great addition. In the aquarium you will often see little lip marks on the glass where algae used to be. The Indian Gold Ring Bristletooth looks very similar in shape, however their bodies are lighter and they have spotting all over instead of stripes.
These fish can be moderate to care for, especially due to the damage their mouths often suffer during shipping. If their mouth is damaged, they cannot eat, or "suck in" the algae and diatoms that they feed on. Thus, when purchasing your Kole Tang, closely examine their mouth area, and pass on any tang that has redness or swelling on their mouth. Purchasing from a store is preffered, since you can see what you are getting. Although these fish are smaller than other tangs, they still need a large enough tank that will hold the amount of live rock that would be needed to provide algae and accumulated detritus and diatoms. If the tank is too small, then swimming room is compromised, however, eliminating live rock to provide more swimming area would decrease natural foods, putting the Kole Tang at risk for starvation. Using the minimum tank size resolves this issue.
Like the others of its genus, the Yellow-eyed Tang or Kole Tang is one of the more peaceful surgeonfish, making it a good companion in a community reef or fish only tank. If they are the only tang, which is preferable, add them last to any peaceful community tank. It should not be housed with aggressive species but rather more peaceful fish. It can be kept with a variety of tank mates including some of the other genus' of surgeonfish that have a peaceful disposition and different diet. For example, the Kole Tang's 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. Watch compatibility as it can be a target of aggressive tank mates and will become stressed and fall ill. Avoid aggressive tangs and add your Kole Tang first if housing with other tangs, even if they are on the more "peaceful" side of the tang personality spectrum.
To meet their need for plenty of live rock, the minimum tank size is 75 gallons. It should be mature, with diatoms and detritus already formed, and have plenty of light to provide algae growth. They will benefit even more when live sand is the substrate, since they can easily obtain food from the surface, as opposed to coarse substrate, which can trap detritus, making it inaccessable to your Kole Tang. This set up will help accommodate this constant feeder with food and swim room. They do better in lower temperatures from 72 to 78˚F (23 to 26˚F), pH that is also constant from 8.1 to 8.4, and good water quality made possible by a good quality skimmer! Provide some crevices or caves for them to sleep in at night.
For more Information on keeping marine fish see:Guide to a Happy, Healthy Marine Aquarium
A Group of Very Dark Kole Tangs
A favorite for reef aquariums, the Yellow-eyed Tang or Kole Tang eats a different kind algae than the other surgeonfish!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.
Yellow-eyed Tang - Quick Aquarium Care
- Aquarist Experience Level: Intermediate
- Aquarium Hardiness: Moderately hardy
- Minimum Tank Size: 75 gal (284 L)
- Size of fish - inches: 7.1 inches (18.03 cm)
- Temperament: Semi-aggressive
- Temperature: 72.0 to 79.0° F (22.2 to 26.1° C)
- Range ph: 8.1-8.4
- Diet Type: Herbivore
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Habitat: Distribution / Background
The Yellow-eyed Tang or Kole Tang, Ctenochaetus strigosus, was described by Bennett, in 1828. They were originally in the Acanthurus genus as Acanthurus strigosus, yet later renamed Ctenochaetus strigosus. The genus Ctenochaetus is Greek for "comb hair" and this is one thing that separated them from the Acanthurus genus. Those "comb hair" teeth gain them the name "bristletooth" because they have several rows of comblike, small, flexible teeth that they use to scrape algae rocks and flat surfaces. Their common names are Bristletoothed Surgeonfish, Goldring Bristletooth, Goldring Surgeonfish, Slender-toothed Surgeonfish, Spotted Bristletooth, Spotted Bristletooth Surgeonfish, Spotted Surgeonfish, Yellow-eyed Surgeonfish, Yelloweye Surgeonfish, Kole, and Goldeneye Tang. The names are descriptive of their distinctive features.
They are found in the eastern Central Pacific and are endemic to the Hawaiian Islands and Johnston Island. They inhabit shallow to deep lagoons and outer reefs; areas saturated with highly oxygenated water from strong tides. In their natural habitat, they are commonly found at depths up to 40 feet (12 meters), but can be foumd as deep as 69 feet (113 meters). They mainly feed on detritus, however they will eat other benthic algae and weeds as well. Kole Tangs are seen singly as adults and do not form bonded pairs. Juveniles may be in loose groups.
From 1955 until 2001 the Yellow-eyed Tang, along with three of its close relatives, were grouped together and identified by Randall as the Strigosus Complex. Also included in this complex:
- The Indian Gold Ring Bristletooth, C. truncatus
- The Bluelip Bristletooth, C. cyanocheilus
- The Red-spotted Tang, C. flavicauda
All four of these fish are extremely similar, differing primarily by slight variations in their color patterns and originating from different regions. Each of these is now described as its own species The Yellow-eyed Kole Tang most closely resembles the Indian Gold Ring Bristletooth C. truncatus, being 'yellow-eyed' but with spots instead of stripes.
- Scientific Name: Ctenochaetus strigosus
- Social Grouping: Solitary - Small groups as juveniles.
- IUCN Red List: LC - Least Concern
The Yellow-eyed Tang or Kole Tang is very similar to its Indian Ocean counterpart, the Indian Gold Ring Bristletooth or Spotted Yellow Eye Tang, C. truncatus. The variation of this species is quite attractive with a light colored body and many blue horizontal stripes (20 or so). There are blue spots on much of the head and they can have elongated tail fin. There is a broad yellowish ring encircling much of the eye, and eye itself is edged with a blue ring.
Its adult pattern is also quite similar to that of the Striped Bristletooth C. striatus. The Yellow-eyed Tang can be distinguished by its more truncated tail and the yellowish ring around the eye, both missing on the Striped Bristletooth. Juveniles are yellow and the top of the dorsal fin and the bottom of the anal fins are lined in blue, they also have a blue ring edging the eye.
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 scraping 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. The males grow up to 7.1" (18 cm) and females are smaller. They can live up to 35 years, which is 10 years less than some other genus of surgeonfish. (Choate and Axe, 1996)
- Size of fish - inches: 7.1 inches (18.03 cm)
- Lifespan: 35 years - Up to 35 years. (Choat and Axe, 1996)
Fish Keeping Difficulty
Bristletooth 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 rock work and the sand of the aquarium it can be a good specimen, and also if it accepts prepared foods.
The Kole Tang needs a lot of water movement that will create an oxygen rich environment, rather than a placid aquarium. It will do best in an environment that provides consistency in water conditions, water quality, decor and fellow inhabitants. They are continuous feeders and they need to be provided a proper diet with plenty of live rock to provide detritus build up and algae growth. This accumulation is only possible in a tank that is mature or at least 9 months old. Tangs are susceptible to nutritional disorders which may cause color loss and LLD (lateral line disease) and to bacterial infections resulting from deteriorated water conditions. Consequently, they will need vigorous filtration, protein skimming, and regular small water changes. Tangs 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.
- Aquarium Hardiness: Moderately hardy - Check mouth for damage. Avoid such specimens.
- Aquarist Experience Level: Intermediate
Foods and Feeding
The Yellow-eyed Kole Tang is considered an herbivore. In the wild they feed on detritus, a thin film on the substrate containing many nutrients including dinoflagellates (minute marine protozoans), diatoms (unicellular algae), benthic weeds and algae, as well as 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.
- Diet Type: Herbivore
- Flake Food: Yes
- Tablet / Pellet: Yes
- Live foods (fishes, shrimps, worms): Some of Diet
- Vegetable Food: Most of Diet
- Meaty Food: Some of Diet
- Feeding Frequency: Several feedings per day
Your Kole Tang will spend a good deal of its time picking at the rock and sand as well as the aquarium glass, scraping and sucking in algae and detritus. Frequent water changes are not necessary, rather normal water changes at 10% biweekly or 20% monthly are fine.
-Large Tanks 100 gallons and over, once water is aged and stable can be changed 10% bi-weekly to 20% monthly, depending on bioload.
Fish only tanks:*
-Large Tanks 100 gallons and over, once water is aged and stable can be changed 15% bi-weekly to 30% monthly, depending on bioload.
For more information on maintaining a saltwater aquarium see: Saltwater Aquarium Basics: Maintenance. A reef tank will require specialized filtration and lighting equipment. Regular water changes done bi-weekly will help replace the trace elements that the fish and corals use up.
- Water Changes: Bi-weekly
Minimum tank size is 75 gallons. Provide lots of live rock rock arranged so there is plenty of surface space for algae to grow and for detritus to collect. Do not house in a nano tank, as they will outgrow it too fast and it will cause aggression. Provide a mature tank with a sandy substrate and stable water parameters. Light should be high enough to provide algae growth. They do better in lower temperatures from 72 to 78˚F (23 to 26˚F), because lower temperatures in water provides higher oxygen saturation. The Yellow-eyed Kole Tang will do well at the normal ocean salinity of 1.023 and pH between 8.1 and 8.4, however both of these qualities, especially the pH should be stable. They appreciate at least an open area above to swim openly when they feel the urge and they love areas with strong water movement. Yellow-eyed Kole Tangs will swim at all levels of the tank, yet prefer the bottom most of the time. They, like all tangs or surgeonfish, will wedge themselves in between rocks or in a crevice at night.
- Minimum Tank Size: 75 gal (284 L)
- Suitable for Nano Tank: No
- Live Rock Requirement: Typical Plus Hiding Places - Arrange them in a way so one area collects detritus and diatoms.
- Substrate Type: Sand
- Lighting Needs: Moderate - normal lighting - Enough for algae growth.
- Temperature: 72.0 to 79.0° F (22.2 to 26.1° C)
- Breeding Temperature: - Unknown
- Specific gravity: 1.023-1.025 SG
- Range ph: 8.1-8.4
- Brackish: No
- Water Movement: Strong
- Water Region: All
The Yellow-eyed Kole Tang is another one of the few very peaceful tangs when it comes to their interations with other fish! They should be housed alone, without another Kole Tang, since they do not form bonded pairs in the wild. All others in this genus do form bonded pairs, so if you want a pair, try a different species. Do not house your Kole Tang with others from their same genus either. This is due to their territorial nature however it may be done in a 10 foot long tank.
Your mellow tang should not be housed with aggressive species of fish, but rather with more peaceful fish. Still, they should be added last in a peaceful fish only community tank or peaceful reef environment. If housing in a larger tank that is hundreds of gallons, other tangs can be added, however in this case, add your Kole Tang first. A few pointers are to avoid tangs of a similar body shape and those that eat the same natural diet and only from different more peaceful 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. Always watch for compatibility as the Yellow-eyed Kole Tang will be a target for aggressive tank mates and will become stressed and ill. Introducing a new surgeonfish into an aquarium that already houses one or more can be a challenge. It is best to initially introduce several juvenile species together at once, rather than adding a new one later on. If it has to be done, rearrange all the rock work and anything else that is moveable to break up boundaries before adding the new comer. 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.
The great thing about the Yellow-eyed Kole Tang is that they are fine in a reef setting with corals, and they will graze on the detritus and algae accumulating between your corals. They are great janitors!
Inverts are also safe from predation, although a copepod or two may be ingested if they are scurrying along an area of algae that your tang just happens to be eating!
- Venomous: No
- Temperament: Semi-aggressive - Peaceful towards non-tang fish.
- Compatible with:
- Same species - conspecifics: No
- Peaceful fish (gobies, dartfish, assessors, fairy wrasses): Safe - Add last into a peaceful community tank.
- Semi-Aggressive (anthias, clownfish, dwarf angels): Safe
- Aggressive (dottybacks, 6-line & 8-line wrasse, damselfish): Monitor - Large dottybacks may be too aggressive. Damsels are too aggressive. Line wrasses should be okay.
- Large Semi-Aggressive (tangs, large angels, large wrasses): Monitor - Avoid more aggressive for the genus tangs. Add this tang first if housing with other peaceful tangs.
- Large Aggressive, Predatory (lionfish, groupers, soapfish): Threat
- Slow Swimmers & Eaters (seahorses, pipefish, mandarins): Monitor - Mandarins should be fine.
- Anemones: Safe
- Mushroom Anemones - Corallimorphs: Safe
- LPS corals: Safe
- SPS corals: Safe
- Gorgonians, Sea Fans: Safe
- Leather Corals: Safe
- Soft Corals (xenias, tree corals): Safe
- Star Polyps, Organ Pipe Coral: Safe
- Zoanthids - Button Polyps, Sea Mats: Safe
- Sponges, Tunicates: Safe
- Shrimps, Crabs, Snails: Safe
- Starfish: Safe
- Feather Dusters, Bristle Worms, Flatworms: Safe
- Clams, Scallops, Oysters: Safe
- Copepods, Amphipods, Mini Brittle Stars: Safe
Sex: Sexual differences
The male Yellow-eyed Kole Tang will be larger and may demonstrate some color change during courtship. Females initially grow faster, however, males catch up and pass them in length, as they become adults.
Breeding / Reproduction
The Yellow-eyed Kole Tang male reaches sexual maturity at 15 months and the females at 9 months. Males are larger than females and like other tangs, they are open water spawners and only form pairs to spawn. They are the only species that do not form bonds with each other. The male will exhibit color changes during spawning to attract a female and ward off any challenging males. A pair will break away and rise upward toward the surface and release their gametes. These little floating fertilized eggs are spherical and have a single oil globule to aid in their buoyancy and dispersal. Once the egg hatches, the larvae look like little kites with a long snout with a small mouth, and they stay in this state for up to 68 days, being the genus with the longest larval stage. During this time, they fall prey to fish and other marine animals. Once they reach around 1 inch, give or take (23 to 33 mm), the larvae are then changed into the juvenile stage. When they are ready to join the reef, the larvae settle out of the water column and develop into these 1” juveniles, seeking the protection and food sources of the reef and seagrass habitats.
The Yellow-eyed Kole Tang has not yet been bred in captivity.
For information on breeding and the development of the fry, see: Marine Fish Breeding: Tangs.
- Ease of Breeding: Unknown
Tangs produce less body slime than other saltwater fish and have been termed “dry skinned” fish by some. This makes them very susceptible to Cryptocaryon (saltwater ich) and other diseases. The most common ailments are bacterial diseases, Hole-in-the-Head Disease, Lateral Line Disease, and parasitic infections such as protozoas (including Cryptocaryon), worms, etc.
For Crypt, 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. As for treatment, some tangs are sensitive to copper because they have an important microfauna in their digestive system, soprolonged or continuous use of a copper treatment is not advisable. It is also said that pellets soaked in garlic may help fend off Marine Ich.
Providing a vitamin supplement (including vitamin C) can help provide for their nutritional needs, and vitamin C can help reduce Lateral Line Erosion (LLE) which may be caused by activated carbon. Enriching foods can be done by soaking dried pellets with liquid vitamins, adding vitamins to the food, or adding a liquid vitamin into the water. Some hobbyists also report success with supplemental foods such as previously boiled or frozen zucchini, broccoli, spinach, and leaf lettuce.
The best routine is a quarantine tank and a stress free environment with good quality veggie foods, places to hide and a quiet area for the aquarium.
Diseases that Surgeonfish and Tangs are susceptible to:
Marine Ich (white spot disease), Marine Velvet and Lateral Line Erosion (LLE)
For more information see Fish diseases.
The Yellow-eyed Kole Tang is usually available at retailers and on the internet. Even then, they are seasonal and not available in the winter. They range in price from $40.00 to $55.00 (Dec 2015).
Animal-World References - Marine and Reef
Hawaii Division of Aquatic Resources
Reproduction, growth and mortality of dole, Ctenochaetus strigosus
By R. Langston, K. Longenecker, and J. Claisse; July, 2009