On Sun, 1 Jul 2007 07:57:04 CST, "Dan Robinson"
wrote:

I want to get some larger snails for my ponds. Maybe some Japanese Trapdoor
snails or Mystery/Apple snails. Does anybody have a pond that is
overflowing with them that can sell me some cheaply or good source? Are
there any big reasons why I would not want these in either a koi or a lily
pond.
Thanks
Dan Robinson
Houston, Texas.

Snails do carry a parasite that does lives a cycle on our fish.

The life cycle of the parasite is quite complex. A fish-eating bird
(typically a great blue heron or kingfisher) eats an infected fish. The
black spot or worms are released and grow to sexual maturity in the bird's
intestine. The adult worms pass eggs with the bird's droppings. When the
eggs reach water, they hatch into free-swimming organisms which then
penetrate snails for further development. Finally, after leaving the snails
they burrow into the skin of fish and form a cyst. The fish surrounds the
cyst with black pigment that gives the disease its name. If an infected
fish is consumed by a bird, the cycle repeats itself. Copied from:
http://www.in.gov/dnr/fishwild/publi...isease.htm#bla

That said, in a koi pond, they like snails, they call them Escargot. ;-)
Only snails that survive those ponds are in the filter. It is really hard
to keep the common pond snail out of a pond system.

As far as the Apple Snail, my understanding is they will eat anything green
in the pond, so chomp, chomp, to the water lilies.

If I remember rightly there was a story told by Roark that he had a couple
in his small koi pond (at the time). No plants, they were there to eat
algae. One of his trees grew a branch that finally hung in the pond, next
day it had been stripped clean to the water line. The snails, as snail
will, sucked the surface over to the limb and ate it. ~ jan
------------
Zone 7a, SE Washington State
Ponds: www.jjspond.us