Best Snail That Don't Breed

A single nerite snail would do the trick.  The horned ones are particularly good algae eaters if that appeals.

[Post modified by fcmf to amend spelling from 'netrite' to 'nerite' in case anyone's doing a search for something that doesn't exist.  ]

I got my horned nerites from MA.

I've had nerites in my tanks for years. I even still have two I bought in 2011, though their shells are very much showing their age.

However, I do need to warn you that although nerites don't overpopulate the tank with baby snails, if you have male and female of the same species they will lay eggs. These eggs look like sesame seeds stuck all over the decor. They won't hatch, and while they can be scarped off hard things, they are impossible to remove from wood without also removing the surface of the wood. The reason they don't produce baby snails is that the newly hatched snails need brackish water to develop in.
I have mixed nerite species. I once made the mistake of buying 3 the same and they laid eggs everywhere. There is a thread showing the nerites I've had in the last few years, each of the photos show a different species. https://forums.thinkfish.co.uk/gallery-showcase/snail-photos/ The photos on page 7 of that thread show what old snails can look like.

This is very informative, thank you Sue

Leave it in a place where you can monitor it whenever you walk past the tank so you'll know if it has moved. If it doesn't, take it out and sniff it every day - gently because the smell of a dead snail stays in the nose for hours so you don't want to take a huge sniff
Nerites keep their trapdoors clamped shut when out of water. If yours doesn't do this, it is dying. If the trapdoor is clamped shut, very gently pull at one edge with your finger nail. A healthy snail will quickly pull it away from your nail.

Some shop workers just rip a snail off the side of the tank, which damages them. If you need to do this, gently slide the snail along the glass, it will soon let go.
Some shop workers pick up dead snails from the bottom of the tank.




A tip for when you do have a healthy snail - they often end up on their backs. If they are close to something they can grab hold of, they can right themselves easily. But if there's nothing close by, you'll have to do it. And before the fish in the tank start to pick at the exposed snail.

Nerites keep their trapdoors clamped shut when out of water. If yours doesn't do this, it is dying. If the trapdoor is clamped shut, very gently pull at one edge with your finger nail. A healthy snail will quickly pull it away from your nail.

I think the trapdoor was shut when I took the snail out.

Great news.