Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Surgeon fish and Tangs

Paracanthhurus hepatus, Regal tang
Paracanthhurus hepatus, Regal tang


There are few available fish in the marine hobby that has such wide appeal as the tang family. Suitable for any type of aquarium from fish only to reef tanks, they can play an important role in controlling algae in any tank.

Tangs are laterally compressed with tiny scales, long continuous dorsal fins and a terminus mouth. However the one thing that distinguishes tangs from other fish species is the spine that extends on the caudal peduncle. This sharp spine is well a well-developed defensive mechanism that can inflict serious damage on other fish and people should the fish feel threatened. Extra care should be taken to ensure that the spine doesn’t get caught in any nets when transferring the fish to a new tank.


Most Tang species reside in shoals throughout most of the world’s coral reefs, with a few exceptions being the larger plankton eating species. However, in a small captive environment, their need for personal space and territory becomes apparent. When kept in close quarters, they can become aggressive towards conspecifics and similarly shaped or coloured species.

Tangs are very active and very fast swimmers and require as much room as you can provide for them. A minimum size tank should be at least 4 feet long to allow for swimming room, anything bigger then that is better. They are fairly shy fish and easily startled. With ample hiding room they will feel more comfortable in the tank, stress less often and as a result be out in the open more often.

When agitated they can use their very sharp spine as an effective weapon. As the fish points it's spine towards you it protrudes from it's body and is as sharp as a scalpel. It is believed that some species of Tangs have poison glands near the spine and excrete some toxins onto the spine before attacking. Further study needs to be done to determine the type and potency or even if there is any sort of toxin in them.


Most tangs are primarily herbivores and feed mainly on macro algae in the wild, therefore they require a lot of vegetable mater in their diet. Vegetable matter can include seaweed (nori), blanched romaine lettuce, spinach, broccoli or zucchini. Even through they will adapt to feeding on meaty foods such as brine shrimp, if fed a constant diet of them without any vegetable matter they will quickly loose condition and will slowly starve to death. Vitamin supplements should be added to the food whenever possible to keep their immune system strong.
If given the chance, Tangs will eat constantly which will quickly pollute the water and are generally considered messy eaters. Extra filtration should be used if housing and tangs.


It's vital to ensure that tank water is well aerated to ensure the health of these fish. They are one of the first fish to suffer should the water become low in dissolved oxygen.
Tangs are prone to carrying diseases such as Cryptocaryon iratians, Brooklynella and Amyloodinium (marine velvet). They should be quarantined and carefully observed before being introduced to the aquarium. They are also very responsive to medical treatment and seem to be able to withstand the onslaught of these disease.
Water quality should be maintained at the highest level possible to avoid stressing the tangs out and leaving them more readily susceptible to outbreaks. Another common ailment found on tangs is Head and Lateral Line Erosion (HLLE).


This is the largest group of tangs with 40 known species, they are the only genus of Tangs found in all tropical reef locations.
Achilles Tang A. achilles - A highly desirable tang, the Achilles Tang, is one of the more difficult Tangs to keep alive in the aquarium. They are hard to acclimatize and have been known to go on hunger strikes for long periods of time. They can become aggressive towards tank mates as they age and require a lot of open swimming room as they are very active fish. They will reach a maximum size of 9 inches.

A. coeruleus

Atlantic Blue Tang is one of the few Tangs found in the Atlantic ocean. They go through three colour phases as they mature starting at a stripped brown, then going to yellow and finally to a solid blue colour at maturity. They adapt well to aquarium life, however most specimens collected already have adult colouration or nearly completed adult colouration, the younger you can get them the more readily they will adapt. They can reach a size of 8 inches.

A. japonicus

This is one of two very similar looking species of fish that are commonly referred to as a White-faced Powder Brown Tang. It's very important to be sure which of the two species the fish is as the A. japonicus is much more likely to survive in an aquarium. The A. japonicus has a larger white patch under it's eyes, reaching down to it's mouth, and the yellow colouration is mostly located on it's body by the fins. These fish can adapt fairly easily to life in an aquarium and will reach 8 inches.

Powder Blue Tang A. leucosternon

The Powder Blue Tang adapts to aquarium life fairly easily. They can be kept in small groups in a large enough tank or singly. A fish in top health will have a pitch black head and bark blue body. IF the body or head appear faded, the fish is stressed and care should be taken to remedy the problem. If bars appear on it's body, it's in attack mode and other fish in the tank will be in danger. They can become fairly aggressive towards tank mates and do not get along with butterfly fish. They can grow to 13 inches in length.

A. nigricans

This the other of the two very similar looking species of fish that are commonly referred to as a White-faced Powder Brown Tang. The A. nigricans have an extremely poor survival record in captivity and should not be purchased. The A. nigricans have a small white patch under each eye and the yellow colouration is located on it's fins and caudal peduncle spine. They can grow to 9 inches in length.

A. olivaceus

Although rarely seen, the Orange shoulder Tang occasionally makes it into the aquarium trade. They adapt well in captivity, however they are extremely aggressive and should be kept alone in the tank or with fish that are able to fend for themselves. They can grow to 14 inches.

A. pyroferus

A fish of many looks, the appearance of the aptly named Mimic Tang can vary greatly throughout it's life. As a juvenile it closely resembles some members of the Dwarf angelfishes (genus Centropyge) to ward off potential predators since the angelfish have a naturally aggressive nature while it's peduncle spines are growing. The type of angelfish they mimic will depend on the location from which they come. Adults are a bluish grey colour. Only juvenile specimens should be purchased as they will adapt to captive life a lot easier then adults. Only one specimen should be kept in the tank to avoid aggression.


These are also known as the bristletooth tangs and will scrape algae off the rocks. They are the only group of Tangs to change colouration from juvenile to adulthood, however the changes don’t take place at any specific stages of their development so maturity can't be determined by colouration.

C. hawaiiensis

The Chevron Tang or Hawaiian Bristletooth Tang is uniquely coloured fish that loses it’s bright colouration as it matures. The Chevron Tang got its name for the chevron type markings found on the body of juvenile specimens. They are still relatively new on the market and fairly rare so information is fairly limited. They are difficult to acclimatize to captivity but after it adapts it’s a hardy fish that eats a great deal. They are slow growers and can reach a size of 8 inches.

Kole Tang, C. strigosus

Known as both the Yellow-eyed Tang and the Kole Tang, this fish is a great algae eater. Juveniles area bright yellow colour, similar to the lemon peeled angelfish and darkens up to a brown colour covered in yellowish spots. Most specimens available in the stores already have their adult colouration. They can gt up to a length of 8 inches.


The distinguishing characteristic of the Naso Tangs is the presence of two spines on each side of the caudal peduncle as opposed to the single spine found on other members of the Tang family. They are also called the Unicorn fish for the fleshy hornlike growths that form on the frontal lobe of the male fish of a couple species. Most members of this genus aren't suitable of home aquariums due to the large size they grow to and vast amount of swimming room required.

N. lituratus

Simply referred to as the Naso Tang, since it's the most common and one of the only members of the genus remotely suited to life in a home aquarium. They can reach a size of 19 inches and should only be kept in the largest of tanks. In the wild they are normally found either singly or in pairs with small shoals being an exception. They can be fussy eaters at first but once it recognizes what's meant as food for them they are quite hardy.

Naso Tang, N. unicornis

The Unicorn Tang is the only other Naso Tang I've ever seen offered for sale. Again these tangs to about 20 inches and require a lot of space to swim and hide. Their unique horn makes them a very unique looking fish. The horn continuously grows with age and is more prominent on the males.


Members of this genre aren’t suited for life in an aquarium. They are the largest members of the Acanthurus family growing to be over two feet. One interesting thing to note about them is that they have poisonous spines, all fish that are damaged by the spine tend to die fairly soon afterwards.


Although this genus has only one species it's probably the most widely recognized tang available for sale.

Regal Tang, P. hepatus

This very popular species has many common names mainly Regal Tang, Blue Tang, or Hippo tang. The Regal Tang can be kept in small groups if provided with a large enough tank. They are hard to acclimatize to captive life and are highly susceptible to ick outbreaks, more so then most other tangs. They require a lot of light, food and pristine water conditions and they don't react very well to medical treatments. The recent high demand for these fish coupled with their poor survival rate in aquariums have put the wild stock in danger of being over fished and it's becoming harder to find them in fish stores. Adults reach a length of 14 inches.


Members of this genus are commonly referred to as Sailfin Tangs for their full large solid fins. They are the smallest of all the tangs and are the most suited for aquarium life. These colourful active fish make a great addition to any aquarium. All seven different species have managed to make it into the hobby at one point or another and continue to be a favourite among hobbyists.
Zebrasoma. desjardini - The Desjardin Sailfin Tang is a relatively peaceful hardy fish that has a stunning appearance. It's best to acquire only healthy juveniles and avoid fully grown specimens. Adults tend to acclimate very poorly in a captive environment, while juveniles will adapt fairly easily. They can grow up to 15 inches in length.

Yellow Tang , Zebrasoma. flavescens

This is the most popular of all the sailfin tangs commonly called the Yellow Tang due to it's brilliant solid yellow body. Young specimens adapt well to captivity. Yellow Tangs become territorial as they grow and can start picking on other fish, however they will be most aggressive towards other Zebrasoma's. They only grow to about 8 inches in length.

Zebrasoma. gemmatum

The Spotted Sailfin Tang is the rarest of the group and almost never seen in the hobby. There is very little information available regarding this species.

Zebrasoma. rostratum

The rare Black Sailfin Tang is one of the most sought after Tangs available. The intensity of the black colouration has no comparison. This peaceful fish will gladly graze algae and seaweed within the tank leaving most other tank mates, inverts and corals alone. It is relatively non-aggressive and shouldn't be kept with other members of the Zebrasoma genus. It does best kept singly.

Brown Sailfin Tang, Zebrasoma. scopas

The Brown Sailfin Tang has different colouration throughout it's life. As a juvenile it can appear similar to the Pacific Sailfin and Desjardin Sailfin Tangs as well as potentially having a Yellow Phase making them look more like the Yellow Sailfin Tang. They are best acquired as juveniles and will adapt readily to aquatic life. The grow to about 7 inches in length.

Pacific Sailfin Tang, Zebrasoma. veliferum

The Pacific Sailfin Tang is similar in appearance to the Desjardin Tang except its dorsal and anal fins are more rounded while it's caudal fin has more of a "V" shape. The Pacific Sailfin can reach a size of 14 inches. They adapt to captive life easily, however they become more aggressive as they grow and age. Best kept singly and added to the tank last.

Purple Tang, Zebrasoma. xanthurum

The Purple Tang or Yellow Tailed tang is one of the most delicate Tangs available. They are hard to keep in an aquarium for a long time and often go on hunger strikes. It's best to acquire a small specimen as they are extremely difficult to acclimate as they get older. Once established in a tank, they are very territorial and require a lot of room to hid and swim. Unlike most other Tangs they mostly rely on meaty foods as a diet and prefer live foods whenever possible. They will grow to about 8 inches. 

Acanthurus leucosternon, Powder Blue
Acanthurus leucosternon
Powder Blue Tang

Acanthurus lineatus, Lined Tang
Acanthurus lineatus
Lined Tang

Acanthurus pyroferus, Mimic Tang
Acanthurus pyroferus
Mimic Tang

Ctenochaetus strigosus, Goldring Bristletooth Tang
Ctenochaetus strigosus
Goldring Bristletooth Tang

Naso lituratus, Orange-spine	Unicornfish
Naso lituratus
Orange-spine Unicornfish

Paracanthhurus hepatus, Regal Tang 
Paracanthhurus hepatus
Regal Tang

Zebrasoma desjardini, Desjardin's Sailfin Tang
Zebrasoma desjardini
Desjardin's Sailfin Tang

Zebrasoma. xanthurum, Puprple tang
Zebrasoma. xanthurum
Purple tang

Zebrasoma flavescens, Yellow Tang
Zebrasoma flavescens
Yellow Tang