Unfortunately not in that tank
A. They require different temperatures,and if a goldfish tank water goes over 65 for a long time it can actually compromise the oxygen in the water for them.
B. That tank is to small for a shubunkin, they need a 15 gallon tank to them selves at least.
If you want to add some more fish for you tank, look into a single gourami, some platy's, some types of tetra's like long skirts, lemon, and neons to name a few. There are many options to add just make sure that fish you add are tropical and wont get over 3 inches.
15 years in fish industry