Will my fish pick fights?

Hi Everyone.! I'm stopping off at Petsmart today to buy myself 2 fish. The 2 I was hoping for were the Red Rosey Minnow and the Comet Goldfish. You can see them at petsmart.com. ANYWAY, if I buy them both and put them in one tank together, will they pick fights with each other because they're different breeds? Thanks! =)