Ramshorns do not eat healthy plants. I have them all over my tanks they do not hurt anything. I rather like them. They are a wonderful indicator of overfeeding. You will have to find a different culprit for your disappearing plants.
Actually that's only partially correct. There are actually several species of snails that in the aquarium trade go by the name "Ramshorn." Some won't eat live plants, but others will. So it's not enough to say you have a snail that your local pet store called "Ramshorn," you need to know the scientific name of which snail you have.
The Brown/Black Ramshorn (
Planorbis cornea) and Red Ramshorn (
Planorbis rubrum) are generally understood to be completely plant safe. These can be recognized by the fact they are typically solid colored, and rarely grow to larger than 1" in diameter. While they will most certainly munch on dead/decaying plant matter, reports of these eating living plant matter are exceedingly rare.
The Columbian Ramshorn (sometimes called the Giant Ramshorn),
Marisa Cornuarietis, on the other hand is a voracious plant eater, and some specimens will actually prefer eating live plants to other food sources (such as detritus or commercial fish food). These are easily recognized by their yellow and brown striped appearance (though a word of warning, there are some examples of more solid-colored brownish or yellowish ones, though this seems to be relatively rare). Despite the fact that (other than the coloring) they look essentially the same as the Brown/Black/Red Ramshorns, this snail is from a completely different biological family; indeed it is more closely related to the Apple Snail than it is to the other Ramshorn snails seen in the hobby. These are larger than the other Ramshorns, being capable of reaching about 2" diameter when full grown.
So, was a Ramshorn snail the culprit? The answer: it depends.
