Just throwing out my experience with nem color change. I got this nem back a year and 9 months ago from Charlie. It was a bout twice as big and more of a standard rainbow color, very rich and darker in color. When I moved it to my mixed reef tank 1 year and six months ago it hid under a rock and shrank and lost a lot of color. It came back out very hungry and sat in the same place ever since. Once it recovered it had the purple dots on the tips and has usually been just a slight variation of the rainbow. Recently I have been keeping just the leds on from the led/t5 combo, to try to eliminate some algae (as pictured in the first picture below). It wasn't looking the same so I ran just the t5's and noticed that it looks different to me, more different in the last 2 months and has taken on a slightly different variation of the rainbow color, maybe more orange/yellowish, definatly as vibrant as a sunburst (second pic, t5's only). Its funny because this guy has split in the past and in its new tank with halides it tripled in size and looked more standard rainbow color. Ill post some original pics when I get them off the other comp for comparison. Pics were taken with the iphone 5s.
View attachment 21652 View attachment 21653
View attachment 21652 View attachment 21653