Last month pet stores began selling genetically engineered fluorescent zebra fish, called GloFish, and I was first in line. Never mind that California has banned transgenic pets, and animal-rights activists nationwide cry foul: What's the point? The fish are technological marvels -- that's the point. Scientists began adding fluorescence genes plucked from jellyfish and coral to zebra fish during the late '90s to make them glow in the presence of toxins, and thus help keep our waterways clean. The $5 gen-mods also happen to look spectacular beneath a black light; they fluoresce neon red. In this case, environmentalism delivers a bankable fringe benefit.