Is my saltwater aquarium good enough for an invertabrate?

I have a 120 L tank with 2 tomato clownfish, 2 yellow tailed damsels, a purple fire goby and a candy striped shrimp. I have lots of live rock and dead/live rock with a few polyps. I have a Canister Biological Filter with 5W UV - 400L/H. I also have a wave maker machine. I am really intrested in saltwater invertabrates. My question is can my tank handle an invertabrate like an anemone and hardy invertabrates that does not grow big and do invertabrates foul the water or help clean it? Can you give me advice,tips and what kinds of invertabrates are good for my tank that I can handle. I have been running my tank for 4 months. Thanks