The yellow tang
, or Lau'i-pala, in Hawaiian
, is a beautiful entirely yellow disc-shaped member of the Sergeant
family of marine fish
. Its bright coloring and general hardiness make it the second most popular fish in hobbyists' reef aquariums
. The short snout of the species has evolved for the specialized task of grazing on algae
which grows on rocks, and the mouth and surrounding skin has toughened to withstand impacts with the rough reef surface. Like other closely related species of fish, they have a number of small spines protruding near their tail, which serve the dual purposes of defense and an anchor while sleeping.
The natural habitat of the yellow tang is the shallow waters of the Pacific, particularly around the Hawaiian islands.
Outside its natural habitat, the yellow tang is generally happiest in temperatures between 75 and 79 degrees Fahrenheit, with a tank salinity of 1.025 and a water pH of 8.1 to 8.3. Yellow tangs are generally peaceful among other non-surgeon fishes, but their behavior amongst other tangs is unpredictable, depending on the individual fish. They are generally happy in large schools of five or more yellow tangs, like those found in the wild, but the behavior of yellow tangs in any school with fewer members is unpredictable; if new tangs are introduced to a tank with established tangs, it is generally recommended that the tank be rearranged. Yellow tangs also seem to get along well by themselves.
Yellow tangs are herbivorous and will graze on algae and eat most anything green, though it is not unknown for them to also eat the occasional brine shrimp. Members of the species do not require any sort of water flow, but will be happier and healthier if the aquarium has even a mild current. The minimum tank size for this fish is 55 gallons.
Tangs are hardy and easy to keep for the beginning marine aquarium enthusiast, but are extremely prone to the fish disease ick; nearly every yellow tang will contract this disease at some point during its life.
Like any marine fish, there are numerous environmental issues raised simply by its popularity. Yellow tangs are primarily collected in and around Hawaii and are not considered endangered, unlike many of their neighbors in the warm, shallow waters of the Pacific; nonetheless, the Hawaiian islands currently ban the collection of fish in certain legally protected "safe" areas.
Yellow tangs have not been successfully bred in captivity, and as such all specimens that can be purchased at your local pet store were caught live in the wild (and, as you can probably guess, most did not survive the trip.) In a recent (May 2001) biological study, scientists managed to get yellow tangs to breed and produce fry, but were unable to deduce what the fry actually ate; so the truth of the matter is, the fish have been bred in captivity, but no fish produced has made it to adulthood. I leave evaluation of the moral and environmental impact of keeping yellow tangs up to the reader. I see nothing wrong with keeping tangs in my aquarium at this point in time, but I reserve the right to change my mind.