Mystery Snails

I kept mystery snails but simply had to give them up. They tend to burry themselves into the gravel and uprrot plants.

Really?
Mine does not.

Mystery snails are basically apple snails, Pomacea species.
http://applesnail.net/

ps. sometimes I would find newly planted stem plants floating because these guys are dulldozers. Once the stems plants form roots, they're safe.

I got 2 they died 3 days after. However, I now have about 3 baby roaming around my tank about half the size of a pea.
Does anyone know how fast snails grow?

It depends on the temperature, feeding and water quality.

But if they appeared soon after the apple snails died and you haven't seen any egg clutches above the water level, they are more likely some other snail species. More about various snail species from this thread.

zackish, the babies are most likely not baby mystery or apple snails. Apples reproduce by laying big blobs of bubble-gum looking egg clumps up out of the water, then these eventually hatch and the babies fall back into the water. You might check up under the lip of your aquarium though.

What you're seeing is most likely a pond snail or some other more common freshwater snail. I love 'em, but some people don't like them. They don't cause any harm though, at least I claim they don't and I've had them with just about every soft-leaved species you can think of.

I've had mystery snails in a planted tank before, and they did dig a little. So far I can't say they have hurt my plants at all though, and it's really fun to watch them cruising around.

Well I had ivory snails and one of the baby is the same color.