Just for the record Lightning does NOT scare the fish! I've been running it for several years now and have yet to see the first sign of a spooked fish because of the lightning. You have to understand that lightning is a very natural and COMMON component in the ocean. Because of the vast expanse of the ocean a the fish are in almost no harm unless in very shallow waters so for the most part fish don't pay lightning much attention. Here's what I've observed from my ProfiLux based lightning (created from SimuL fixture):
My "Storms" come up slowly and depart slowly. As the main lights dim all the tank goes into sort of their "night time" mode. As the storm gets closer the main lights keep dimming as the lightning increased in frequency and intensity. During the "middle" of the storm all system lights are OFF and lightning is at it's most intense! As the storm departs lightning slacks off and main tank lights slowly ramp back up to their pre-storm state (or the current state if it's changed during the storm).
The whole time the STORM is happening the fish are chilling out and some go into their sleeping area and hang out. After about 10 minutes after the storm everything is back to normal.
I'm just wanting people to know that the lightning, from my experience, does not spook the fish at all and even though it doesn't have any real BENEFIT to the tank it also doesn't HARM the tank. It ranks WAY up there on the COOL factor... at least for me...