1. The simulation of sea urchin fish tank decoration is made of TPR material, which is safe, environmentally friendly, healthy and non-toxic. 2. The product is used for the first time, put it in the fish tank for 2-3 days, replace the water, and then put it back into the water for 3-7 days to put the fish in. 3. Uses: fish tank decoration. 4. Diameter: 13cm. 5. Weight: 125g.