Tank mate(s?) for a Maroon clown in a 40g tank?

[DanG]

I'm looking for ideas on what to put in my tank. There's one maroon who is about 2.5 inches long, 4 turbo snails, 1 peppermint shrimp, 3 scarlet hermits and 4 blue hermits and 2 emerald crabs, one big, one small(the small one was a hitchhiker when I bought some green star polyps).

Any ideas on what to put in? I'd love a yellow tang, but the tank is only 36" long, and I have no upgrade plans for a couple of years. I'm not looking to overstock it, just add a small fish or 2.

Any recommendations?