IotD is a little late to this as news, but I hadn't seen a photo of them until now... this is the GloFish, which was announced to be the world's first genetically engineered pet. Its color is the engineered part; it's fluorescent in day and glows at night.
The company says it's safe if eaten, won't live to procreate in the wild if it ever escaped. It was made by taking an "ordinary" zebra fish and inserting genes from jellyfish or sea anemone.