Nope, just like Goldfish cant burp. I know someone who wanted to test this, so he bought a 13 ct goldfish adn put it in a cup. He then dumped about 5 tablespoon's of bakingsoda in ther. The fish "swallowed" some. The kid was waiting for it to explode, an dit didnt so he letf to go paly outside. Then he came back, and found the goldies floating on the water with a huge stomach wound! I personally didnt witness the event, but i think it is true, plus it is a common myth.