Snail Escape...

Question
My husband and I started a small (10gal.) aquarium last spring.
We have 4 small red-eyed Tetra, 2 small Barb-Tiger, 1 med.
Plecko, 1 grey Guarami (sp?) and 2 pink kissing Guarami (sp?) as
well as 2 snails - 1 "Black Mystery" and 1 "Blue Ivory."

The fish seem to do quite well together - although the grey
Guarami (and this may not even be what it's called, someone
gave it to us... he's named "Leon") anyway, Leon tries to jump
out of the water pretty frequently. Of course, there's a lid on the
tank, so nothing will ever come of that.

The thing that worries me, though, is that our snails keep
"escaping" somehow. At first we thought it was through the
filter, so we put a rock on top of the filter lid. They keep getting
out, though! We don't know how or why - and I'm worried that
one of these times we won't notice for too long and they'll die.

Do you have any idea why they do that and how to prevent it?

Thank you!

Answer
There isn't much you can do to prevent escape other than making sure all of the notches in your top are small enough where the snails can't squeeze through. It's peculiar that they would want to escape - unless they keep getting picked on. Gouramis can be moderately aggressive and can if feeling particuarly mean pick on the snails.

Are you keeping the snails as algae eaters? You can keep chinese algae eaters instead. They won't be able to escape as easily as the snails.

Now you have prompted me to do some research. I have never kept blue ivory snails myself.