No. Not if the paint is dry and even if it flakes off it will only be unsightly. Bonsai plants have decorative statues and stones and they cause no trouble. Cactus grow in very harsh conditions and the only thing you need worry about is over watering. Water is the number one kill of indoor plants.

I used Krylon gloss spray on some lake rocks (to make them shiny and beautiful). I would really love to put them on top of my cactus bowls, not buried in the soil. will the chemicals from the spray leach off into the soil and kill my plants? if you don't know, don't answer please.