What is the blue aura around my Pokemon?

Question

I was transferring a bunch of Pokemon recently, and I noticed that some of the Pokemon had blue aura's around them.

What do these auras mean?

You can see the auras in the cp159 Zubat as compared to the cp135 Zubat in the image below:

Answer 1

Blue auras mean the Pokemon in question was captured recently (likely 0-24 hours old). This confers no bonus and has no advantage or disadvantage.

You can verify this yourself by sorting all Pokemon by capture time. All the blue Pokemon will be at the top.

^source