Is there a scavenger I can keep with a clarkii clownfish?

I'm new to saltwater aquariums, and I just got my first clownfish. I'm feeding it frozen shrimp, but, of course, it doesn't eat it all. I scoop most of it out, but I'm having a hard time getting it all off the bottom of the tank. The clown fish doesn't seem to go for it when it's on the bottom. Is there some sort of scavenging fish I could get that would be compatible with the clarkii clown fish?