i have breed kribs a lot now they will not stop.
when they first started breeding there was a plec in the tank which i witnesses eating the fry.(basically charged them down). but when i took the plec out they are breeding fine (machines) the male has been "servicing" 2 other females. so plec's can be a problem just depends on there size and if there are intimadating the kribs.
kribs are very good at look aftering there fry and will guard them and sheperd them around the tank which is fun to watch