I'm quoting this book directly now:
"...it doesn't contain toxin unless it eats tissue from toxin-producing fish such as the Xanthid crab, angelfish, goby, horseshoe crab, or the blur-ringed octopus. The puffer also ingests some microorganisms and bacteria that prouduce toxin, all of which concentrates in the puffer's liver, skin, ovaries, and certain muscles..." I was wrong about the skin part. Sounds like that O was definately poisoned.
It also says most, but not all puffer species are toxic.
The article is about the Japanese delicacy of eating puffers, even though it costs about $400, and 50 people die per year from ill-prepared puffers.