Narrow-line Puffer behaviors

[NewReefMom]

Hello Reefer,

I recently purchased a narrow-lined puffer to add to my 100g tank. I have some questions about their behaviors.
In the picture below he is laying on the noir clip. At first I thought he was eating but he's just resting on it, probably to get away from the other fish.. one question I have is, is there something out there that I could get to serve as his resting or lounging spot?

Also, he seems to change colors. At times his lines will be completely visible and other times he seems to have more geometric black shapes then lines. Is this normal?

Similar to my Valenti puffer, he prefers to be alone, but I do have a rather clingy blue tang that seems to annoy both my puffers. Lol

Also included a little video of all my lovelies
Sorry for the loud TV in the background.

 

[blaxsun]

I think the color changes are just the visible reaction to stress, etc. When my parrotfish is happy he's all these nice beautiful colors. When he's ticked about something he gets these geometric dark patterns.

 

[lion king]

That is a stress pattern, just make sure your water quality checks out and no one is bullying him. As far as a resting spot, he is just going to pick his own, sometimes you will scratch your head wondering why the heck is doing that.