LKLudlow wrote:

In the last month, I've had one tiny snail multiply into nearly a
forest of them. Some are floating on the water surface, some are on
the walls, and a gazillion of them are on every surface in the
aquarium. What do I do about them? Will they hurt my Cory's and
Danios?

Add a couple of clown loaches to your tank. Eliminates the problem
quickly and reliably.

By the way, if you crush the snails between your fingers, many other
fishes like to eat their remains.