Hi, You can put one of the larger angels with a pygme angel (but not another pygme)....but you cannot put more that one large angel in the 100 gallon. I just got a new majestic angel because he is one of the smallest and least aggressive of the larger angels. I have a ninety gallon which may be small for him when he is full grown. My flame angel is about 2 inches now, and the majestic angel is about 5 or 6 inches now and may eventually grow to 10 or 12 inches. He could care less about the other little fish in the tank including the flame angel. If you get one he needs to be the only large fish in the tank so that he can be the boss as they most likely will not share a tank as small as a hundred gallons with another large fish. The majestic angel is such a show piece in the tank that I do not need another large fish. I just hope I can get him to eat better. He is very shy. Also, large angels tend not to be reef safe with a lot of corals. The majestic angel was also my choice for the 90 gallon as they do not seem to have the need for as much swimming space as some of the other large angels. If you want a peaceful fish why not try one of those blue tags like the "Dorry" in the movie Nemo. I heard that they are peaceful and I think reef safe but not sure. I also read that you can usually only put one tang in a tank that size. Read up as much as you can before you buy any fish. I also love the look of the powder brown tangs, and the powder blue tangs. I read a lot about all of these before I finally decided on the majestic angel. I have only had him for three days. If you want a nice peaceful reef safe fish with a lot of color check out the fairy wrasses too. Lesley