you shouldn't have touch them when its puffing because doing so it get panic more and won't go down, should have let it calm down by itself and turn off the light or cover the tank completely dark instead. It is sad to hear since its a great looking fish too. Fahaka do puff too and fresh water when they puff chance of dying are very high so keep it in mine.
thanks everyone. to be honest i think he is in a better place. I agree with folks who think that the Mbu Puffer should be not be in aquaria, but left alone in the wild. If you really think about it this puffer requires a masterbedroom sized fish tank to properly house this beautiful beast of the wild.