I bought these for my turtle, Xeno, because I thought he would like to play with them. He didn't. I never saw him touch them. His tank is in the front of the house, I am always home, and I hang out with him a lot. He had zero interest in them. I only put about 8 of them in his tank. Within 5 or 6 days, I could see chips in all but one of them. I didn't realize they were painted or I never would have felt safe using them. They are actually white stones. I freaked out when I saw paint missing, because my turtle obviously DRINKS and LIVES in that water. I know that Xeno didn't cause the damage, because like I said, he never messed with them. He is very gentle and never fusses with anything. He doesn't bite or claw at anything, ever. Please, please do not use these in an aquarium. I will be contacting the manufacturer to let them know that these are not safe. :(