What animal venom kills the fastest?

The fastest animal venom to kill is a venom from the stinging catfish or pufferfish. The pufferfish is the only fish that is capable of injecting its victim with enough venom to kill it instantly; the stinging catfish is actually the second most poisonous fish in the world, after the lethally venomous blue ringed octopus (both of which are capable of killing humans). This horrifying fact comes from a paper by the Institute for Ingestive Toxicology out of Germany, which stated that getting stung by a pufferfish or a blue-ringed octopus is “just as bad as getting shot or stabbed.”A human has approximately 1 mg of protein in their blood, whereas a pufferfish has approximately 100 g. Needless to say, this fish will pump you full of its toxic protein! At first, the pain and swelling will go away fairly quickly, but within 24 hours you will likely be vomiting blood, developing kidney and liver failure, and losing consciousness. If you survive this unfortunate encounter with a pufferfish or blue-ringed octopus in your waters (and I very much doubt this will happen), you will then develop immunodeficiencies that are likely to lead to your early demise.