As you can probably guess, the more closely related tangs look more similar.
For example, the genus Zebrasoma contains the yellow tang, scopas tang, black tang, purple tang, gem tang, and I'm sure there are others.
The genus Acanthurus has the powder blue, the Achilles, the powder brown, orange shoulder, and many others.
The genus Ctenochaetus contains the bristle tooth tangs, like the kole tang, chevron tang, and similar.
Other fun facts: the two name latin naming system is called binomial nomenclature. The first letter of the genus name is supposed to be capitalized and the second name lower case, and the whole latin name is supposed to be in italics.