orientalis are good parents, even with eggs, unlike popei who regularly munch eggs (although to be fare ive never seen them even chase a stray larva left in the tank) on the subject of cannibalism with them-i prefer to leave all generations of my orietalis together, even though my adults wont eat the little ones, their siblings will. my theory behind it is that the strongest will survive and morph larger and more robust than if i raised them separately. i have several generations in a 15 gallon tank and as soon as they morph they never really leave the water (i have lots of floating plants, green water and logs..the things a bog!)mine are semi aquatic perminantly once they transform. (and they dont climb the glass trying to get out like some other newts-they are comfortable with the set up). the only way i know for to slow down growth is to drop the temp the larvae are kept in, but if you raise the temp the parents are kept at they might stop too -thinking breeding season is over, or you could transfer the parents to land, the female may dry up after being moved there. honestly though i dont believe it heartless to allow the babies to fend for themselves with each other, this is a common occurance in vernal pools in the wild and assures the next generation is a healthy sock.(although cannibals do express a slightly different body type it is purely a result of this diet of others, not a genetic change in them)