In article , Sue & Bob Hobden
writes

"Kay wrote in message
have a 450 litre filtered pond in its first year. underneath each lily
leaf
are numerous clear jellylike cylinders 3-4 cm long which are obviously
new
life of some kind. the pond otherwise contains iris, oxygenators, 2
goldfisha nd 2 shebunkins. Any ideas what creature lays such a thing-want
to
keep them if not harmful but whatever it is eats the lily leaves!
thanks

Probably water snail eggs. You need the snails to deal with detritus in
the pond, and they won't cause major damage to the lilies.



Water Snails in a pond have the same effect as normal snails in your border,
they do no good whatsoever.

Err, not so. They are beneficial animals to have in a pond.

They will eat the higher order plants in
preference to anything else

Err, not so. They are brilliant at cleaning up algae.

and produce lots of detritious themselves, they
certainly don't eat it!

They produce detritus ( which is what I assume you mean and by which I
suppose you mean faeces) in proportion to their number and size. As do
fish!

Also a carrier of liver flukes during part of their life cycle.

Only a handful of species in the Genus Lymnaea carry liver fluke and
normally only Lymnaea truncatula (aka the Liver Fluke Snail) which is
not exactly common in garden ponds, preferring wet meadows and ditches.
And even if you have that species in your pond, it has first to become
infected from sheep or cattle, so provided you fence those animals out
of your garden, which I imagine most people do (!), then this is no
argument against the vast majority of pond snails.

One saving grace is that fish will eat them when small, and big fish will
crunch even large specimens. (You can actually hear it crunch from
underwater, lovely sound, and then all the bits of shell get blown out the
gills)

Lucky old fish. But if you have fish and no pond snails you will have a
much dirtier pond.

Snails are as natural a part of a well-balanced pond as any other
pondlife, including fish, water-lilies, pond skaters, whirligig beetles,
water boatmen, etc., etc. I don't see why you appear to be prejudiced
against them!!

--
Malcolm