RECOMMENDED FOR A LARGE TANK: we recommend the Under Water Oasis for aquariums 20-30 gallons in size or larger. The product measures 14.25 x 8 x 15 inches, so please measure your tank and make sure that there’s room in it before purchasing. FULLY COLORED AND HIGHLY DETAILED: Each piece is made of a high quality resin that’s been hand painted for fine detail. Safe for your aquarium and fish, we highly recommend rinsing your Under Water Oasis with warm water before placing in your fish tank. FOR FRESHWATER AND MARINE AQUARIUMS: These heavy duty resins are safe for your freshwater and saltwater tanks. The beautiful piece will instantly become a main focus in your aquarium! WEIGHTED DECORATION: All of pieces of the Under Water Oasis are weighted, so they will not shift in your aquarium after you place it where you’d like. They can easily be moved by people, but not by water pressure or a big fish. SHOP PENN PLAX: Penn Plax has a wide variety of Pet Supplies for sale on Amazon. Shop for all of your aquatic needs, as well as for your dogs, cats, birds, small animals, reptiles, and more!