A yellow star in the skin
Xanthophores (say "ZAN-tho-fors") are skin cells that hold yellow color. You can find them in fish, frogs, and lizards.
The zebrafish is a little striped fish that lives in rivers and in many school science labs. Its dark stripes come from black color cells, and the light yellowish stripes between them get their color from xanthophores.
A xanthophore is shaped a bit like a star, with arms that reach out through the skin. Inside are tiny grains of yellow pigment. Some of the yellow comes from the food the animal eats.