It should be noted that the theory of dolphins getting “high” off puffer fish is highly controversial as others have mentioned that tetrodotoxin, the neurotoxin released from puffer fish, is famous for causing paralysis making it more of a poison as opposed to a good time. It is reportedly more potent than cyanide. In fact, a study published in 1990 reported tetrodotoxin as the cause of death of two Atlantic dolphins found dead in a lagoon (Hokama et al., J Clin Lab Anim. 1990).
So what exactly are those dolphins doing with the puffer fish in the BBC documentary??
Hokama et al., Causitive toxin(s) in the death of two Atlantic dolphins. J Clin Lab Anal. 1990;4(6):474-8.