Hmm, there is something present in the tank water column or on the tank surfaces that’s affecting your snails.
First, want to ask how did you clean the tank before adding water and tank equipment?
Did you use any chemicals or glass cleaner stuff, anything like that.
Second, the plants, can’t tell if they’re real or fake in the photos at the moment.
If real plants, where did you get them from and have they been treated with any insecticide or chemicals?
If fake plants, are they from a reputable source and made from plastic and resins or something else?
Also, did you clean these fake plants before adding to tank?
If so, how did you clean the tank?
Lastly, did you cycle this tank?
Some of these questions may be obvious but eliminating obvious causes may help determine what is happening.
First, want to ask how did you clean the tank before adding water and tank equipment?
Did you use any chemicals or glass cleaner stuff, anything like that.
Second, the plants, can’t tell if they’re real or fake in the photos at the moment.
If real plants, where did you get them from and have they been treated with any insecticide or chemicals?
If fake plants, are they from a reputable source and made from plastic and resins or something else?
Also, did you clean these fake plants before adding to tank?
If so, how did you clean the tank?
Lastly, did you cycle this tank?
Some of these questions may be obvious but eliminating obvious causes may help determine what is happening.