You might think it's grand to be a well endowed fish. After all, some female fish prefer mates with larger sex organs, a new study finds. But the guys' prowess has a price. The studs with larger gonopodia, which is what scientists call male fish sex organs, can't swim as fast as their less impressive counterparts, so they're more likely to get eaten by predators. Bigger is better The study was done on mosquitofish, which are like guppies. They're only about an inch long. That's body length. For the appendage, we're talking millimeters. Nonetheless, biologist Brian Langerhans of Washington University...