Pistol shrimp eating cuc

[pirate]

As the title says I have a goby/ pistol shrimp pair and am wondering what to be feeding the shrimp? He was really good for a long time. Now he has eating my hermit crab and one snail. So what should I be feeding him? I don't blame him for anything it's just nature, but I also don't want him to finish off the rest of my cuc. So what do they like to eat beside my cuc?