Saddle Valentini Puffer

[Deathstar]

I picked up the Saddle Valentini Puffer he eat a few of my Hermit crabs and a snail. He also tryed to kill my shrimp. I removed all the hermits and shrimps and just left a few big snails. I also have a starfish the puffer does not bug him.I have 2 other fish a Maroon Clown and a Six Line Wrasse. The Puffer does not bug any of my fish.

What would be a good fish to get to help keep the tank clean?

Thanks,