I had never noticed aquatic snails in any of the Garden’s water features until one day in the upper pond I saw what seemed to be 1000s of them! Apparently when conditions are favorable, the Acute Bladder Snail - Physella acuta can reproduce very quickly. I'm guessing that conditions were just right!
Underwater video of upper pond at 500x speed.
Native to North America, these attractive snails can be found in freshwater rivers, streams, lakes and ponds. How they got into this GNG water feature is a mystery. They normally get introduced by newly added aquatic plants with eggs attached to them. This isn’t the case because we’ve never added any aquatic plants to this feature. Maybe they arrived on the legs of herons that occasionally visit the pond - who knows?
Whatever their mode of travel was they are here to stay. At the moment I'm not really worried about the infestation as these snails only eat dead plant and animal matter. I’ll keep watch on them, but as far as I can tell, they are not competing with anything native.
Nature has a way of always keeping you on your toes!