Valentini Puffer Rubbing on Glass

[a;lksdjf]

I have recently purchased a valentini puffer from the lfs that is currently in a 10 gallon quarantine preparing for a 45 gallon tank. He is about 3 inches long, has no visible skin issues, and happily eats everything I give him since day 1, which is surprising because I hear about a lot of people having trouble getting their puffers to eat. It has been about 4 days now and he has taken to rubbing against the glass all day instead of exploring the interior of the aquarium. Does anybody know if this is caused by stress or disease? I know that brackish puffers will "glass surf" when first introduced and I think he might just be doing that, but some reassurance would be much appreciated because I haven't read anything about saltwater puffers glass surfing.

 

[Angel_Anthias lover]

He might see his reflection on the glass and is trying to fight it