The Uniclife Resin Hollow Tree Trunk Betta Log Aquarium Decorations Ornament Fish House Cave Wood House Decor for Small and Medium Fish Tank is a great way to add some style to your fish tank. Made of high-quality resin and wood, this ornament is perfect for any fish lover. The flat bottom makes it easy to keep in place, while the sandpaper helps smooth out the edges and ensure that the ornament stays looking fresh. With five cave entry/exit holes, each measuring 1.5 to 2 inches, this ornament is perfect for small fish.