It is the tetrodotoxin that makes fugu (pufferfish) such a sort after sushi. Just the right amount gives a pleasant tingle when eating it, a bit too much and you die. Also why you cannot farm them (easily at least), you need the bacteria that they acquire in the wild.
They also have a really compressed genome, with the same number of genes as us in only 400,000,000 bases, compared to humans at 3,000,000,000.
They also have a really compressed genome, with the same number of genes as us in only 400,000,000 bases, compared to humans at 3,000,000,000.