I have a 100G FO tank, with a picasso trigger. I have had him for 2 1/2 years. This is the least aggressive fish I have in the tank, he never bothers anybody; even newcomers. He is about 2", so he is not a big size, by any means. I think if you get a small picasso and add him last, you will be fine. I really believe with triggers, it is the luck of the draw; one might be extremely aggressive the next might be a wimp! Bottom line, if you really want the picasso, it is worth a try. BTW,I have had triggers with angels, and triggers with tangs, and if you are commited to frequest water changes, and have good filtration (that is a must) they will be fine.