We had a family here get sick from eating puffer fish. If not properly cleaned their innards are poisonous..............
Wasn’t there a Columbo episode where Louis Jordan killed someone with peufferfish?
For more precise info...use the Wikipedia page on puffer fish toxin to start off...many other animals have the poison tetrodotoxin...it appears that the toxin is produced by certain symbiotic bacteria that live with it’s host.
The liver of the pufferfish has the highest concentration of the toxin in the beast and is not to be eaten.....
Have fun.....