

Hi bought a few crabs a few days ago and they seem to die really fast. One died with a lost limb due to fighting and this one died look all normal. I'm not sure why they are dying so fast like that. It's not a lot of crabs too like 4 at most? Now only left 3. Second pic is my setup
I have moss in there also. Will they die if they eat moss? I add in leftover fish food and frog food as they have calcium ingredients.