A succulent is a plant such as a cactus that possesses fleshy, thick leaves and a stem capable of storing water. Many pests of succulents do the plants direct harm; ants are not among them. However, ants can cause indirect harm to succulents by introducing harmful pests like aphids and mealybugs. The ants "farm" these insects and harvest their honeydew to feed their colonies. Other indirect harm is caused if the colony nests in the soil around the plant and disrupts its root system.
Determine if the ants you see on your succulent are farming aphids or mealybugs, or simply passing by. Observe the ants' paths. Since they often "hide" their bugs in crevices of leaves or inside rosettes, it is not always easily apparent that they are farming.
Place a small shallow dish of sugar water near the succulent to attract ants away from it.
Eliminate the aphids or mealybugs and their honeydew using a direct jet of water, or wipe the plant down with a soapy sponge. This may take care of the problem if caught early. If the ants continue to bring them in, continue to remove them until the ants move on to easier territory.
Treat the aphids or mealybugs with an insecticide, removing the ants' food source. The ants will move on if they cannot be successful on your plant.