Take coral, hammer it with very tight range of wavelength... POOF, colors morph.
Yeah that's my serious take on it, there is no selective breeding going on, coral farmers aren't breeding squat, and I have a real hard time these species are now just magically all showing up out of no where. And even on the hobbyist side of things, with LEDs being so widely used things tend to look better because you can narrow those wavelengths down and increase intensity specifically to fluorescing wavelengths, where as before whether it was metal halide or fluorescent tube sure there may have been a favorable spike (e.g. 20kK Radium bulbs) but you couldn't increase the intensity at that wavelength and tone down the other wavelengths.
