With all respect, i am good friends of a LFS owner who did tell me lime green(electric tone, neonish), yellow, are most likely dyed pieces. He gets those pieces often and told me the reason those corals live weeks after in our tanks is because the coral is bleached then dyed.
When bleached, it loses all capacity to produce its food(zooanthellae leaves hosting structure), and then the dye is added. These pieces are so stressed by the process and short lived after it that he told me if he doesnt sell them right after they arrive, they will start dying in the store.
Other corals that also normaly get such atrocity done are cabbage coral and kenya trees. The last ones are usually dyed hot pink and the dye is excreted with time, so if you look in the skimmer collection cup, you will notice the pinkish color...the coral will start to become paler and die.
Green regular gonis are known to be short lived, with life spans of 6 months to 1 year. Some have more success, but i really doubt we will ever see someone that kept the yellow or other uncommon color for longer than maybe a month...