Yellow Mimic Tang - Mimic Lemon Peel Tang: The Yellow Mimic Tang is commonly known as Chocolate surgeonfish, Chocolate Yellow Mimic Tang and Mimic Surgeon. When young, they have bright yellow colored circular body and as they grow the bright sulphur color fades. Large varieties of this fish, though rarely available, are dark brown with golden trim. There is not only change in the color of the Yellow Mimic Tang fish but also their fins appear to have dark blue or black colour. Some feel that a brilliant juvenile yellow fish looks attractive in an aquarium when compared to its dark matured color.