The powder blue tang (often called by its scientific species name leucosternon) is one of the most beautiful and coveted fish for marine aquariums. A mature powder blue tang has many different shades of blue, from dark navy to light powder blue, with bright yellow on the dorsal fin and dramatic black markings on the face. However, it is also one of the more difficult fish to keep on a long-term basis. Initial problems are primarily with marine ich, to which most surgeons and tangs are very susceptible. The powder blue tang is extremely susceptible to this parasite, and almost every powder blue in a tank will have to go through at least one bout with ich.

Once a healthy powder blue is established in a tank, it will be a large, fairly aggressive fish. This fish must be the only tang (or similarly shaped fish) in the tank unless it is a very large aquarium. It can become very territorial and nasty to other large fish, and it requires a large amount of swimming room. The minimum size tank for a powder blue is 90 gallons, and the bigger the tank the better.

This fish feeds constantly, and it is best to always have nori seaweed, blanched zucchini or romaine lettuce in a clip on the side of the aquarium. In addition, it needs to be fed regularly with specialized herbivore diets containing Spirulina algae. A powder blue tang is generally reef-safe, as long as it is well fed.