When I lived in Florida, I tried to raise Apple snails in my pond but the next year, all I had was empty shells and my ponds are above ground containers. Could be the goldfish.

I thought about that but I have no empty shells in the pond either.

Chris,
A few years ago I added 20 Japanese 'trap door' snails to my pond and didn't see any for quite a while. Every now and then I see a few. They are very hard to see because they are usually covered with algae and you're not going to notice any movement. Raccoons have an acute sense of smell. Is your pond shallow enough that raccoons can get in and forage with their paws. If it is raccoons getting at them they may be taking them outside the pond to a spot on your property to eat them,__check around the yard for empty shells.

The following are quotes from 'Crystal Creek Pond Supply LLC' where I bought mine:

(http://www.pondkoi.com/trapdoor_snails.htm)

"RACCOONS: If you have raccoons that visit your pond they may eat them. Most county animal control offices have traps you can use to relocate the raccoons. It is not unusual for raccoons to live in the middle of very larges cities. I have seen raccoons live inside city storm drains during the day and come out of the steel curb drains at night to feed."

"WHERE DID THE SNAILS GO? We sometimes get email from people who put snails in their pond and in a few days cannot see them after they disperse. The fast answer to this is that the snails are still in your pond and you cannot see them. They are almost impossible to spot as they are the same color as the rocks and gravel. One way to check is to get a fishing pole and put a lettuce leaf on the hook and lay it on the pond bottom. Come back in an hour or two and you should have snails at the lettuce."

Witz