SNAIL Invasion!!! HELP!!!

[Virago]

My friend's 300 gallon garden pond has been invaded by snails for the first time since she installed it over 20 years ago!
The snails are about 3/8" long, and have been clogging her filters/pumps and leaving their gel-like eggs everywhere.
Are there any solutions besides chemical treatment which risk harming her small pond fish and plants?
Thank you!!!

 

[Alan]

That's a real problem. Snails that small are usually hitchhikers on plants or came in on equipment. The good news is you have options that don't involve chemicals. Manual removal works if you're patient. Pull them by hand when you see them or use a fine net. It takes time but it's the safest for fish and plants. You can also trap them with lettuce or algae wafers sunk to the bottom at night, then remove the whole pile in the morning. For the filters getting clogged, a simple screen or mesh over your intake will stop most of them from reaching the pump in the first place. That alone might solve the worst of it. Some people add assassin snails to eat the smaller ones, though that's trading one snail problem for another in a way. Others swear by reducing feeding and excess organic matter since that's what draws snails to explode in population. Got a photo of what you're dealing with?