RESIN MATERIAL: Aquarium skull is natural resin and free of chemicals.It is safe for fish. Shrimp, fish fry, betta, small fish. Before putting the product into the aquarium, please rinse with water first.Please soak for 10-15 minutes with water before applying.Applicable to fresh water environment, put into the fish tank or aquarium to let the fish shuttle freely among them, add a natural breath to the fish tank. SMOOTH EDGES: The unique shape, rich colors and realistic image not only allow you to enjoy the beautiful fish channel, but also provide a more natural environment for fish, shelter and entertainment. Don't worry about your baby and shrimps playing. DON'T FLOAT: The ornament base is heavy, it doesn't float above water. The small fish can swim in the water and hide in the cave. Aquarium accessories complement any naturalistic look. There are holes on the skull, your lovely pet betta or other smaller fish would be super happy to go in and out the trunk cave to sleep, rest, hide, play, breed. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.