I made these rock hides out of the Great Stuff expandable foam. I spray painted them then added a little detail with craft acrylic paint. My concerns are fire hazards and fumes. It’s in a glass aquarium and one will be close to the a che and light. The other concern is will the spray paintbe safe after drying. these things look great but I don’t want anything bad to happen to Mike Tython. I don’t have tapatalk on this phone so I can’t post pictures but I’m generally proud of these things lol