Are Japanese trapdoor snails truely good to add to a pond?
I read that trapdoor snails: (1) won't multiply and get out of control; (2) will clean up algae; (3) will not eat healthy plants, will only eat the rotting ones; and (4) can survive winters okay in a pond. Before I regret adding 100 to clean up pond's algae, is there any reason not to put them in a pond?
I did a little research and found them interesting but the only drawback I found was that every article I found was geared towards aquarium life, couldn't find anything addressing ponds
They are not going to do any harm. But, don't get the idea that you will be able to do less maintenance work. The impact of the snails on algae, etc is simply not what the hype on internet sales sites would have you think. They have been around for over a century. If they really solved all those issues, everybody would already have them. .....In the plant aquaria world, where everything revolves around algae control, etc., they barely get a mention anymore. They were a big hyped-up fad for a time & long over it. Still, an attractive snail, does a little good & does no harm.
I had them. I didn't notice a difference and then when my koi started flashing from parasites i had a choice. Treat the pond (which kills the snails) or let the parasites multiply.. Needless to say i treated the pond and kilked the snails.. Not worth getting in my opinion.
Perhaps if you describe the algae problem in more detail, you'll get some suggestions. If you're talking about carpet algae that's attached to the walls and is ~1/4" long, that's great and nothing should be done - it is not a "problem." If you have hair algae that's many feet long, snails won't fix that (use hydrogen peroxide). If you have green water, snails won't fix that either (use UV.)
I've had them in my pond for years....I don't know how much they eat but when the water quality starts to go south the snails all come to the surface letting you know somethings amiss...canaries of the pond!