Cleaner Wrasse

[FaRico]

It's just him and a peppermint shrimp in the tank right now. The tank is full of copepods and it's seems like they are still multiplying. I didn't feed him when he came out, and since I thought he was a goner I hadn't feed the tank in 10 days. Come to think if it I only see the shrimp maybe once, twice a week tops. Is there a reason they constantly hide? I have a nanocube 28 gal with about 15-20 lbs of rock.