2 Clownfish

I have a 29 Gallon Biocube and got two new clownfish from a tank full of them at a fish store . They are doing well but the issue I have with them is that they'll fight when near each other . I had them for two days now . One is about .5 inches bigger than the other . The bigger one will dash toward the little one , look like it'll try nipping at it and the smaller one will wiggle its tail at it , than the bigger one swims away . Sometimes they can be with each other . Is this normal ?