Attention: this information was gathered from wikipedia. Please refer to that site for more information.
Yellow tang are in the surgeonfish family. Adult fish can grow to 20 centimetres (7.9 in) in length, and 1–2 centimetres (0.39–0.79 in) in thickness. Adult males tend to be larger than females. Yellow tang are bright yellow in color. At night, the yellow coloring fades slightly and a prominent brownish patch develops in the middle with a horizontal white band. They rapidly resume their bright yellow color during daylight.
They have an arrow-like shape due to their dorsal and ventral fins being almost an extension to their bodies, and a long snout-like mouth used (as with other tangs) to eat algae and seaweeds that suffocate corals. They also have a sharp spine located near their tail. They have become a popular fish for marine aquarists of all skill levels, as the fish tends to be active, hardy, and nonaggressive when kept with dissimilar species.
In the wild, yellow tang feed on benthic turf algae and other marine plant material. In captivity they are commonly fed meat/fish based aquarium food, but the long term health effects of this diet are questionable. However, most experts in the marine aquarium industry express little skepticism that such a well rounded and balanced diet including plant and animal material would be in any way detrimental to mostly herbivorous fishes like tangs, since they still need on occasion, complex amino acids and nutrients that only ocean animals can provide. In the wild, yellow tang provide cleaner services to marine turtles, by removing algal growth from their shells.
Distribution and habitats
In the aquarium
The yellow tang is very commonly kept as a saltwater aquarium fish. They can grow up to 8 inches (20 cm), in the wild, but are introduced to aquariums in the 2″ to 4″ range, some specimens as large as 6″ are occasionally available. Life expectancy in the wild can exceed 30 years. Captive lifespan is typically at least 2–5 years to as long as 20 years in a very large aquarium, with 5–10 years in the average aquarium being typical. “Some,not most, are however likely ‘killed off’ in the first month of care (from hobbyist mistakes, inappropriate tankmates, starvation…)”. Often ranked as a good beginner fish in the marine aquarium industry, the more prudent approach is for them to be kept by a marine aquarist who has at least 2 years or more of experience successfully keeping a marine/reef type biotope. They require an aquarium of at least a 55 gallon “show” tank-(48″Lx21″Hx13W”),at the absolute minimum where a single smaller specimen 2″-3″ may be kept provided it’s done by an experienced marine aquarist who can provide the fish with highly stable water chemistry parameters, very low to undetectable nitrate levels and a highly nutritious,balanced diet of seaweed and high protein frozen or live, meaty foods. A 75 gallon or larger is better for a single specimen, while 100 gallons or 60″ in length or more aquarium is ideal. Like all tangs, they are quite susceptible to Cryptocaryon irritans (a parasite resembling Freshwater “Ich”) and other common saltwater diseases. Marine “Ich” however, is usually quite avoidable in a marine tank as long as it is not introduced from incoming specimens or a rapid, sudden temperature drop in the tank from a heater that stops working is avoided or quickly corrected. There is also no evidence however, to suggest that tangs and other surgeon fishes in general are any more susceptible to marine ich than any other smooth-skinned, scale-less marine fishes. They are also susceptible to poisoning by high levels of nitrate, so care should be taken to keep measureable levels fairly low to less than 30 parts per million(PPM) in whatever type marine ecosystem the tang is housed in. They are semi-aggressive, though normally successfully cohabit with other semi-aggressive fish close to their own size. They are successfully kept as well in a multitude of privately owned aquariums that keep them peacefully and successfully with smaller fish such as chromis, damsels, and smaller clownfish. Tangs can thrive with others in pairs or in a group in large tanks (150+ gallons). If kept in groups of two or more specimens, at least a 72″ length aquarium is strongly recommended. Other suitable tankmates include fish such as cardinalfish, large clownfish, lionfish, eels. They are reef-safe, and can be kept with any invertebrates in a reef aquarium. In essence, the yellow tang is a rewarding, peaceful marine aquarium inhabitant for a moderately experienced marine aquarist that can provide them with ample housing, a good diet, and optimal water conditions.