Water Wildlife

    Water Snails

There have always been arguments for and against the various types of water snail.  They can indeed be useful scavengers, but their numbers have a habit of increasing very rapidly, and they will often cause damage to plants.  They also add to the nitrate levels in the water, by contaminating with their own detrius, which possibly negates their value as scavengers of rotting plant material.  Add to this their habit of nibbling at the eggs, or in some cases, even the young, of other pond life; and of acting as intermediate host to certain parasites, and you might feel that you'd rather be without them.

Having said this, I have to admit that, try as I might, I have not yet been able to exclude snails of one kind or another from my ponds or even aquariums!  They arrive on plants, as eggs or small snails, or on stones added from other "wet" areas.

As I write this, it is early February, and the odd dead leaves that I lift from the pond, even in this cold weather, have blobs of elongated jelly containing tens or even hundreds of tiny eggs.  It is hard to keep control over numbers, but maybe worthwhile trying to reduce the numbers of large ones.  We have 36 species of pond snail in Britain, and the Great Pond Snail I personally feel is certainly one too many.  With a brown, conical shell of anything up to 5cm or 2 inches in length, and tapering to a point, it is our largest water snail.  It can be recognized also by it's inabilty to withdraw it's tentacles completely.  Snail lovers will claim that it munches through decaying matter and algae at a useful rate; but it will also vary it's  diet with best lily leaves, new shoots, and - especially in the winter - the occasional newt or other less speedy creature that might be lethargically napping through the cold weather in the bottom of the pond.  

This site was last edited on:- 20 October, 2000 22:52