I have 3 nems, my oldest is 7 years old, one thats is 3 and one that is 2. The oldest is probably 8x12 and has never split because splitting is a survival mechanism, that they do when ever conditions are not good. Mine sit 6 inches under 2x250 MH
and the nems sit directly under one of the 250 bulbs. So when I see that they are under T5's long term I have to ask what is long term? So after 7 years I think I can state that nems need high lighting to prosper. They may survive under T5's but IMHO
they need MH
or high end leds for "long term". I have no stats but following 3 different forums, it seems that the survival rate for nems are less than 20 percent. Many people get them right away with a couple of clowns because they cant wait and want to think their set up with poor lighting and poor water conditions are different that the thousand before them. Second off a lot of people new to the reef hobby get stucked with a bleached nem because of lack of knowledge. And a experienced reefer may keep a nem alive under T5's I hate to see that advice given to newbes or people with their first nem because it sets them up for failure. The other thing is people come onto the forums after they purchase a specimen and ask how to take care of it. The time it takes to post that question is longer than the time it would take to Google and educate ourself before the purchase. If we all continue to buy what we want rather than what our set up will support, then we are guilty of contributing to killing off our oceans rather then being part of the solution.
Off my nem soapbox.