The tang species Ctenochaetus strigosus is known under many different English names, such as Kole tang, Yellow eye kole tang, Yellow-eye tang, Goldeneye tang, Spotted surgeonfish, Bristletoothed surgeonfish, Goldring surgeonfish, Spotted surgeonfish, Slender-toothed surgeonfish, Yellow-eyed surgeonfish, Yelloweye surgeonfish, Goldring bristletooth, and Spotted bristletooth.

The word Kole comes from Hawaii and is pronounced “coal-e”.

Between 1955 and 2001, the Kole tang (Ctenochaetus strigosus), the Bluelip Bristletooth (Ctenochaetus cyanocheilus), the Indian Gold Ring (Ctenochaetus truncatus), and the Red-spotted tang (Ctenochaetus flavicauda) were grouped together and identified by Randall as the Strigosus Complex. These four species are very similar in appearance and can be easily confused with each other. They do however originate from different parts of the ocean and their colour patterns vary slightly.

Ctenochaetus strigosus has not been evaluated for the IUCN Red List of Threatened Species.

In addition to being a popular aquarium species, the Kole tang is sometimes used as food. Reports of ciguatera poisoning exist.

Geographical range, habitat and habits

The Kole tang is found in the Central Pacific. In the Eastern Central Pacific, it is found around Hawaii and the Johnston Island. In the Western Central Pacific, it inhabits the waters of Australia.

This is a reef-associated species with a depth range of 1-113 meters / 3-370 feet. It is primarily found down to 12 meters / 40 feet. You can encounter Kole tangs in shallow to deep lagoons and outer reefs where they live over coral, rock and rubble. They prefer environments where strong tides keep the water highly oxygenated. Adults live alone while juveniles may form loose groups. This is primarily a day-active species.

Size and appearance

The largest scientifically measured Kole tang was 14.6 cm / 5.7 in.

The Kole tang is deep brown with numerous horizontal yellow stripes running along its body. The head is adorned with small blue spots. The eye is big and encircled by a pale yellowish ring.

Juveniles may have spots instead of striping and are yellow at the top of the dorsal fin. A blue ring edges the eye and the bottom the anal fin is also lined in blue. 

Just like the other surgeons, the Kole tang has a “scalpel” (a sharp spine) at the base of its tailfin which is used for protection and to establish dominance. When the spine is not in use, the Kole tang will keep it folded down inside a groove.

Unlike most other tangs of the family Acanthuridae, the Kole tang has 8 dorsal spines instead of 9.

Kole tang care

This is a fairly hardy species famous for its algae eating capacity. It is considered a medium maintenance fish. It is not advisable to house a Kole tang in an aquarium smaller than 90 gallons / 340 litres. It is one of the shyest species of tang and it is very important to provide it with good hiding spots in the aquarium, including crevices in which it can seek shelter during the night. Ideally include lots of rockwork in the set up. Ample amounts of live rock and live sand will increase the food supply and allow the fish to carry out its natural feeding behaviour. There must also be plenty of space for swimming.

Adult specimens live alone in the wild, but it can be possible to house them in groups in the aquarium. They may become aggressive towards each other, so keep an eye on them. The Kole tang may also fight other species its own genus. It is safer to house it with tangs that look different when it comes to body shape and colour pattern. The Kole tang is a relatively peaceful tang and housing it with aggressive species is never recommended. Also avoid species with the same particular feeding requirements unless your aquarium is very big and prolific.  

The Kole tang is considered coral safe and invertebrate safe.

The recommended water temperature when keeping Kole tangs is 72 - 78° F / 22-25.5° C. Keep the specific gravity in the 1.020-1.025 range and the pH-value at 8.1-8.4. Well aerated water is of imperative importance. Provide strong water movement in at least one part of the aquarium.   

The Kole tang has a relatively small “scalpel”, but you still need to be careful when handling this fish. If you are injured by the spine, it can cause discoloration and swelling. The pain may last for several hours and there is a high risk of infection.

The Kole tang is sensitive to prolonged copper treatment because copper can harm the important microfauna present in its digestive system. Since members of the family Acanthuridae do not produce a lot of mucus, they are more inclined to fall prey to external parasites like marine ich. In the wild, the Kole tang is known to seek out cleaner wrasses of the genus Labroides to keep skin parasites in check. In the aquarium, it can be a good idea to provide your Kole tang with at least some type of cleaner, e.g. cleaner shrimp or Neon Gobies (Gobiosoma spp.).

Feeding Kole tang

The Kole tang belongs to a group of fishes known as 'bristle tooth' or 'comb tooth' tangs. These fishes are equipped with several rows of small flexible comb like teeth (up to 30 teeth) which they use to feed detritus rich in minute algae. They will spend most of their time lifting and sifting through detritus and algal material in search of food. The mouth is protrusive and works like a vacuum cleaner. It is often possible to actually see lip marks on the aquarium glass when a Tang kole has cleaned the area form algae. The Kole tang is famous for its fondness of hair algae.

Natural algae growth and detritus accumulation should be encouraged in the aquarium since this makes is possible for the Kole tang to carry outs it natural feeding behaviour. Unless you have a huge and really prolific aquarium, you need to supplement the naturally occurring food to prevent nutritional deficiencies. Ideally feed your tang many small rations throughout the day instead of just one or two major meals. An insufficient diet will increase the risk of disease, e.g. lateral line disease (LLD).

In addition to naturally occurring food, you can for instance give your Kole tang marine algae, boiled zucchini, and blanched romaine lettuce. It is also a good idea to add a high-quality flake food rich in vitamin C to the diet, preferably one that contains spirulina. The Kole tang loves all sorts of dried seaweed, e.g. nori. This species is commonly viewed as an herbivore, but it actually needs occasionally servings of meaty food to stay happy and healthy in the long run. You can for instance feed it mysid shrimp and brine shrimp.

Breeding Kole tang

It is hard to sex Kole tangs based on outer appearance. The male fish may change his colours somewhat while courting.

We have no information about Kole tang breeding in aquariums.

Surgeonfish - Tang Articles:

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