Certain types of snails are more adept than others at escaping the fish tank. Nerite snails and Mystery snails are the two most notorious varieties for this! Keep the little escape artists in by putting a lid on your tank. If you want your snails to be able to reproduce, you need the water level to be a couple of inches below the lid. Your betta fish has similar requirements anyway, though. Betta fish are good jumpers and sometimes launch themselves right out of the tank! For this reason, you need to use a covered tank and ensure the water level is not too high. Snails are tricky and sometimes can escape even a covered tank by some miracle. Don't worry too much about it, though. Some people have no trouble with this, while others struggle a lot. If you want to entice your snails to stay in the tank, make sure it's decked out! Get plenty of live plants, feed them algae pellets, and take good care of their environment. By keeping up with your care routine and putting a lid on the tank, you lower the risk of your snails climbing out of the tank.