Do water changes every two weeks. I'd do about 15%. A clown can prob. live through the ammonia after another few weeks, but only one as like others have posted, the waste boosts the natural cycle. Your tank is still VERY new. Although with introducing as much life into it as you have may have sped it up some. Did you remove the dead snails? Try some emerald crabs or some spider crabs (make sure they're reef safe, I have a non coral denominated tank and if that's what you want later you don't want something that will eat your coral)and get a few new snails. Get a good clean up crew going first. Don't add anything else for a month or so at least. Let the tank naturally cycle via water changes. Slowly add more livestock. Crabs are good for eating any excess food once you do introduce fish. But with a starter tank, no fish at that size I'd say you only need two at best. I believe emerald crabs are omnivores and will eat algae as well. You have to remember the smaller the tank the more damaging the death of a single fish can do. If you don't remove it immediately or have an outstanding clean up crew, you'll have the same problem if it was to happen again.
Once you do introduce fish (most prob. wouldn't recommend it this early but again, damsels are hearty, yet annoying. You can get a small one and it would likely help the process along with a good clean up crew. Just don't be surprised once your tank is established to desire to give it back to your livestock supplier.)
What kind of filter are you using?