The Indian Goldring Bristletooth (Ctenochaetus truncatus) is also known as the Spotted Bristeltooth and Spotted Yellow Eye Tang. There is a marked difference between the colouration of the juveniles and the adults. Being members of the Acanthuridae family, also known as Surgeonfishes they have a retractable razor sharp spine on either side of the caudal area. These are used for defense and possibly in territorial disputes and can inflict significant damage.
The Indian Goldring Bristletooth is in the sub family Acanthurinae whose members have large numbers of bristle like teeth, which are used for scraping organic matter off the surface of the reef and from sifting sand.
The juvenile Indian Goldring Bristletooth is very attractive fish with an overall bright yellow colour. They really stand out on the reef. There are thin blue lines on the dorsal and anal fins as can be seen above. As the fish ages so the body darkens and goes a light brown colour. This can be seen in the image below. The area around the eye darkens slightly to a golden color giving the fish its name of Goldring. White spots develop across the body.
As it ages further so the body color darkens and the spots on the body become more accentuated. The blue lines on the dorsal and anal fins remain, but are not as conspicuous. They obtain their scientific name truncates because the tail is short and straight. Other members of the family have more elongated tails. There are no obvious differences between the sexes but the males become more vibrantly colored during mating. They grow up to 16 cm in length.
INDIAN GOLDRING BRISTLETOOTH IN THE WILD
The Indian Goldring Bristletooth is fairly common on the reefs in Tanzania and is often seen grazing on the reef. They are seen singly and in pairs, often with other members of the subfamily. They are fairly skittish fish and are quite fast moving when there is a diver around.
The Indian Goldring Bristletooth is mainly on shallow reefs although sometimes they are seen on rubble areas. They are found across the Indian Ocean. Their range does not extend into the Pacific. They are most common around the 12 to 15 meter range but can often be seen on shallow reefs at around 3 to5 meters.
The Indian Goldring Bristletooth (Ctenochaetus truncatus) use their bristle like teeth to scrape nutrients off the reef and off sand. They use their teeth to sift off the nutrients which are then sucked intothe stomach. Their natural diet is composed of algae, detritus as well as organic matter including dinoflagellates, diatoms and other small organisms.
Indian Goldring Bristletooth are often seen in pairs. At times one of the pair is more vividly colored and this is usually the larger specimen which is assumed to be the male. Other than that little seems known of their mating habits and we have never seen them spawning.
Indian Goldring Bristletooth are kept in aquariums but are not as popular as their close relative Ctenochaetus strigosus which are seen as being more attractive visually. If one intends keeping the Indian Goldring Bristletooth they should be kept singly or as mated pairs to prevent territorial disputes between two males or two females. They are fairly placid fish and may be bullied by more aggressive species. Given that the bulk of their natural diet is scraped off rocks or sand, to be fair to the fish one would require quite a large tank to provide sufficient food for an adult. A full grown fish of 16 cm requires a large grazing area and because of this careful thought should be given before placing one in your tank. They require a lot of live rock and preferably live sand.
Indian Goldring Bristletooth are not commonly caught by fishermen in Tanzania due to their feeding habits and the improbability of taking bait. They are netted occasionally but given their diet they may contain toxins and Ciguatera poisoning is a danger.