Pods the size of rice ?

Ok I have pods the size of rice and bigger . Like steroid ones . How do I reduce their number ? There are so may that a couple zoo colonies get irritated by them. To the point of being closed a lot. Would a mandarin work ? Could they eat ones that big or is there something else?

 

I have a b/w clown and a semipicasso/snowflake clown. the tank is 7.5 gallon cube with a 5 gallon sump. The things is these guys are everywhere. Out even in the light. They come out when I feed the fish and just sit there a look at you. Its really weird. I think there is enough to keep a mandarin happy but I would want to make sure he could eat other stuff incase he did decimate the lot of them.My luck he never would.