i have 1 red and 1 tiger oscar about 2", 1 2" green severum and 1 4" clownloach, would it be safe to add 3 silver dollars?

edit: by the way they are in a 120g tank

You might get away with 2 or 3 but you will have a lot of large water changes when they all get big

What concerns me is that you only have 1 clown loach. Clown loach are social fish and need some of their own kind around to be happy. The minimum for clown loach is 3, so you need to get 2 more clown loaches or rehome the one you have