So sorry for your lose. One thing I often recommend to people keeping puffers is to watch out what kinds of powerheads you are using. They are not strong swimmers and can get stuck and hurt so easily. Especially when puffed. Koralia's are great for puffers. I have seen my burrfish puff up near one and she just gets pushed back around the tank
The burrfish actually sleeps or lays ontop of the koralia quite often. They are very safe with puffers.
Sadly this happens all too often. Im not going to lie...Its happened to one of my puffers once with a maxi-jet and it also died.
Sorry again and I hope you find another dogface. They are such amazing fish!