These colorful fish make interesting picks when owners follow some basics.
By Timothy A. Hovanec, Ph.D.
Tangs symbolize the colors and beauty of the saltwater aquarium. They are included in the family of fish containing the surgeonfish and doctorfish and are a diverse group of fish.
The category includes standards for almost any saltwater aquarium and others that are considered off limits due to their large size or inability to adapt to captivity. Tangs, surgeonfish and doctorfish belong to the Acanthuridae family of fish that contains six genera: Acanthurus, Ctenochaetus, Naso, Paracanthurus, Prionurus and Zebrasoma.
Some references say that only fish belonging to the Zebrasoma genus within the Acanthuridae family are tangs. But this convention has not been strictly followed, as there are fish in the Acanthurus, Paracanthurus and Naso genera whose common names include the word ”tang.”
Another reference says that ”tang” applies to the smaller fish in the Acanthuridae family. Here, it will mean fish in the Zebrasoma genus. The Zebrasoma genus includes seven species of fish. Care and housing tips for the Zebrasoma can also be applied to other common fish in the saltwater hobby, including the blue tang (Paracanthurus hepatus), Naso tang (Naso lituratus) and the Achilles tang (Acanthurus achilles).
The word ”tang” in German means seaweed. These fish do eat seaweed in the general meaning as they graze large amounts of algae off the reef.
Tangs and almost all Acanthuridae have many common traits, which include that they are laterally compressed. Their bodies are flattened so that if they were lying on their sides, they would be flat like pancakes. Their mouths are adapted to picking algae off the reef and they have narrow caudal peduncles leading to broad but flat tail fins.
- The yellow tang (Zebrasoma flavescens) is one of the most recognizable fish in the saltwater hobby. They occur across the Pacific from Hawaii to Australia. In the wild they school in large groups, creating a moving yellow wall of fish against the blue water that is hard to forget. They are known to be aggressive against each other and other Acanthuridae, so a general rule is to either have only one in the aquarium or a group of at least five. This is so that no one fish gets picked on too much. All the fish need to be added at the same time.
- The sailfin tang (Zebrasoma veliferum) from the Indo-Pacific can get large and needs a bigger tank. This fish gets its common name from the shapes of its dorsal and anal fins that extend way out from the body like sails. The fish is generally brown with a yellow snout populated by freckles. It has five vertical yellow stripes that are spaced along the body from right behind the eye to the tail. This fish is peaceful but not with other sailfins or Acanthuridae.
- The Desjardini tang, also called the Desjardini sailfin tang (Zebrasoma desjardini), comes from the Red Sea and Indian Ocean areas. This fish is shaped much like the sailfin tang, but instead of being predominantly brown in color it can also be mostly white to gray with many vertical yellow stripes along the body. These fish get large and need a lot room. Again, while more aggressive than the previous two species, the Desjardini tang can be housed with other fish that are not of the same species or family. It will graze on filamentous algae.
- A great addition to any tank, the yellowtail or purple tang (Zebrasoma zanthurum) only gets to about 8 inches in length (which is small compared to the sailfin and Desjardini tangs), and the body is a deep blue-purple color except for the bright yellow tail. These fish come from the Indian Ocean and Red Sea and are not hard to keep as long as there are lots of algae.
The caudal peduncle is the part of the fish that connects the body of the fish to the tail fin. From this common trait, this family of fish gets the general name surgeonfish. On each side of the caudal peduncle is a sharp spine, usually in a color contrasting to the body. The fish can use the spines for defense. Hobbyists sometimes receive cuts while handling them.
Feeding and Care
Retailers may want to tell customers to provide food heavy in algae for these fish to survive and thrive. An old feeding standby is to add lettuce to the tank each day. It might not have nutritional value, but gives the fish something to do besides chase each other.
For better diets, retailers can suggest adding blanched spinach or broccoli. The market now has several brands of dried algae that come as large leaves that can be attached to weights and dropped into tanks. The tangs will vigorously attack these leaves.
In nature, tangs constantly forage among reef structures. Feeding small amounts several times a day rather than one or two large feedings would better mimic the tang’s natural behavior.
The constant feeding behavior leads to the next question: How many tangs should be in a tank? Many believe that too many tangs in a tank are detrimental to the fish because there is not enough natural algae growth. This may lead to nutritional problems, such as lateral line or hole-in-the-head ”diseases.”
It seems a good idea to not have too many tangs in a tank from the standpoint of balancing the algae growth with the grazing pressure of the fish. Unfortunately, there is no easy formula to determine how many fish are just right—it depends on the species, the tank setup and other factors.
It is best for retailers to have conversations with customers. They can ask questions such as “Is there a fair amount of algae growing on the surfaces in the tank? How many and what species of tangs and surgeonfish are already in the tank?”
Another question is: ”What is the size of the aquarium?” Tangs need lots of room to swim. Ideally, the minimum size tank for a tang is 55 gallons. Some would argue that size is too small.
Almost all tangs are reef safe and are important members of a reef tank because they keep the algae growth, which can be high because of the intense lights, in control. Every reef tank can benefit from having at least one tang in it.
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