The most poisonous snake is not the coral or death adder but is the sea snake is not the coral or death adder but is the sea snake . The sea snakes venom is 50 times more powerful then the king cobras. Sea snakes do not always inject their venom, nobody in the world knows why. The venom has a slow effect but is fatal 25% of the time . Fishermen are most likely to be victims as they step and handle carelessly .