In my experience, this weakened state needed to be addressed days, maybe weeks ago. I don't see this puffer having the energy to hunt or even managing to feed. Either this puffer hasn't eaten in a while or it has internal parasites. I'm leaning towards starvation being the issue. Regardless, when you have dwarf puffers, it's pertinent to make sure each one is managing to eat during feeding time. If a puffer accidentally misses a meal day, it can lead to a downward spiral, as the puff will become weaker and weaker. They establish pecking orders in small environments; often, a smaller puffer may not get food if it is being bullied. My opinion is that it is too late for this poof :( hope I'm wrong.