From my experience yes, had a Silver about 9" he had been in the tank for months, forgot to turn on moonlights one night found him dried up next morning the punk jumped through the small opening in back where hob filters where. This was a while back and now I have a 16" Jar but have always remembered to turn moons on so that is the extent of my experience with moonlights but if you never get them use to the lights then it probably wouldntt matter. I think its more whats routine for the fish then the actual lights.