As someone who swallowed a live goldfish every year for four years as part of an undergraduate St Patrick's day tradition ... I can promise you it won't hurt you. It is, however, one of the nastiest things I've ever done in my life and every year I swore I'd never do it again. Getting multiple fish down at once will prove difficult, because after the first one goes down, you might be fighting the urge to vomit. The best tip I can give you is to put them in alcohol before you down them. Pop the fish in a glass with the cider/beer and drink them down. Don't attempt to chew them ... just don't.