Nemateleotris magnifica, and I brought it home Sunday to join my others. At the same time, I also bought a beautiful Pictichromis diadema, but it suffered too much stress on the way home and going into the new aquarium, so it died the next morning.
Now the weird thing about the fire fish: for a period of about 20 hours, it disappeared COMPLETELY. As in, IT WAS NO LONGER IN THE TANK. I jiggled around the decorations to flush him out of hiding, and he was utterly absent. From what I've read, they're a spastic sort of breed, and are known to jump out of aquariums. I thought this must have happened, and one of the cats ate him. But then this morning, he was back, seeming as happy as it's possible for a fish to be.