Should I add another clownfish?

Hi, I currently have 1 ocellaris clownfish in my biocube 29. It's about 2.5 inches long. I researched that clownfish are happier in pairs, so I was thinking of getting a smaller clownfish for company. However, Im scared because some people say that clownfish become territorial when they are in pairs and will attack your hand in the tank. Is this always true? I don't have an anenome, but I have some corals that they might host and protect. Thanks!