Puffer Fish

S1 E4: These tropical fish have a signature defense. But inside some is more protection--a potent toxin made by microbes. Those with spines have even more security; and there’s a third defense that some of these fish share. A neurotoxin on the skin and inner organs that’s produced by bacteria. It can be deadly to many creatures including humans. Oddly, some blowfish with this toxin are a delicacy.