At what point can I move the otala lactea babies to the adult tank? Is it just size or shell thickness? There are two in particular that are basically the same size as their parent but their shell isn't as thick as the adults. I'll be posting pics on Mon, the largest baby has coloration unlike any of the others, very dark pronounced striping.
Personally I find the biggest problem facing baby snails is finding their food. I find that when left in large tanks SOME babies will wander off, go to sleep in some remote corner and just never really slime back to the food the next night, or ever. I find there's a higher mortality rate in some species. When kept in tubs these snails will never be far from food and they often grow quicker, plus more (if not all) will survive and grow. However my observation is mainly on Achatina species. I find that P.isabella do not have this problem, and survive and grow well in large tanks from the moment they hatch.
I have not experienced problems of older or larger snails accidently crushing younger ones.
So based on this my suggestion would be that they should be fine to go in with the adults in the larger tank when they are large enough and speedy enough to reach their food easily from the fursthest reaches of the tank. I also suggest spreading the food around while they are young.
There's no definite rule really, people have varying opinions.
I've never kept babies separate from adults, but I've only had 3 clutches (two of which were garlic snails). It may be a good idea with larger species, but for the smaller ones I'm not sure it's necessary.
I think food isn't the only issue really I have had problem with baby fulicas. They started to eat parrents shell if they don't find calsium. They hitchhiked in parrents shell back to food plate and slept there and when adult came the ate parrents shell because they where too sleepy to find they way to calsium.
I have reunited fulica babies with parrents when they are about 3cm shell length so they are like little buracell bunnies and can make their way to food and hang around almost at same time that fully growns are up too =)
So it would be best to wait until their shells are a bit thicker then even though a few are basically adult size? I was only thinking about the ones that were bigger, the ones growing at a slower rate were staying in the tub I've had them in. Maybe I'll try and find another container and just move the bigger ones to that so they have more room but are still surrounded by food.