To determine this, we need a photo showing the stomach, which is not on the upper surface of the puffer.
A decent side-on photo is needed, or you can judge this yourself without trying to get a photo. if the shape of the fish narrows in the stomach area, then it has a problem.
You started a thread six days ago about your puffer not eating,
http/www.fishforums.net/index.php?/topic/431318-amazon-puffer-wont-eat/ , but you have not given either of us further info that is needed to help you and your puffer.
Tank size in dimensions (eg. ~120x30x30cm)?
What filter are you using?
How did you "cycle" the tank in readiness for the puffer i.e did you "fishless cycle" the tank and filter by maintaining 2-4ppm ammonia for ~6 weeks?
What are the ammonia; nitrite; nitrate readings of the tank currently (ideally using a liquid test kit)?
Have you changed any water since adding the fish? If so, roughly how much of a percentage?
What food have you tried over the past six days and did you remove uneaten food after ~12 hours?
Does the puffer's beak look overgrown and need its first of regular trims?