I have a Niger Trigger in my 90G and he is really awesome. He gets along with everyone in the tank. This type of trigger is well suited for a tank your size as well. A clown gets pretty big, and I have always wanted one but I don't have the right size tank for him though. As everyone said, QT
him before you put him in the main tank. In fact, I would probably add him last if you can. Mine is not very aggressive, but each one has different personalities. That is a great skimmer by the way.