Lithops are tough plants that can survive high temperatures. Growing them in a different environment can be quite challenging. If your Living Stones start to look unhealthy, the causes could be Overwatering, Lack of Sunlight, and Pest Infestation. Overwatering If you see signs of discoloration and the leaves looking mushy, these are signs of overwatering which is the number one cause of death for succulents. When you see discoloration, it means the roots are rotting and fungal infection has spread. The first thing you have to do is to cut out the infected parts by using a sharpened and sterilized pair of garden shears or knife. Remove the plant from the pot and shake off the excess soil. Look for the rotting roots and cut them off. Leave Living Stones in a dry place and allow the succulent to dry out completely. Fill out a terracotta or ceramic pot with standard potting soil or cactus mix and re-plant Lithops. Lack of Sunlight Etiolation might not kill your succulent - if the problem is addressed right away. All you have to do to remedy the situation is to give Lithops enough sunlight. Within a few days, you will see the leaves starting to look healthy. Pest Infestation The spider mite is the most worrisome pest for Lithops. These creatures find a home in the crevices between the leaves. Spider mites can cause fungal growth in Living Stones. A sure sign that your succulent plant has spider mites in residence is the appearance of white spots on its leaves. Other dangerous pests that could harm Lithops include mealybugs, aphids, and thrips. You can get rid of these pests by spraying Lithops with neem oil or by wiping the leaves with insecticide soap.