I have a niger in my reef too... had him in there since I started the reef about a year ago. Never bothered a soul (except for a fire goby my wife tried to add). The niger has never bothered any of the anemones, corals, crabs, shrimps, or starfish that we have had. He is very curious about anything we put in the tank (he often bites at the bags while we float new stock before adding to the tank), but doesn't bother it once it's in the tank. He often gets right up close to the new animal (like he's going to bite), but I think he's just checking it out.
He is still a trigger though, and triggers as a species are rather agressive. Just because a few people on the board have nigers in their reef, that doesn't mean that you won't get one that eats everything. Remember, every fish is different, they all have their own personalities.
Good luck.
[ July 24, 2001: Message edited by: jacksonpt ]