No, mystery snails are *very* docile and will not fight with other fish. The issue is, other fish may eat the antennae off the snail (I had this happen to one of mine thanks to my betta). When the antennae are missing, the snail can't see, and will have a harder time eating, and will hide more than usual or move more slowly. If you notice this happen, and that your snail's antennae are getting shorter, (carefully) remove the snail from the tank and put them in a clean, 2.5 gallon tank to recover in. It should only take a few days, probably less than a week. Don't be surprised if your snail doesn't move very often while it heals, just check every morning to see if the snail has moved from one spot to another, and your little friend is fine.
You can try to introduce the snail back into the old tank, but I wouldn't suggest it. Mystery snails don't do well when moved around a lot.
Hope this helps!
Date published: 2018-02-08