Our new portal viewer allows for easy access to your fish tank ensuring that plants underneath the surface of your aquarium have access to light! This also helps your fish have access to food and prevents them from accidentally eating duck weed or other floating plants. The circle design is a beautiful shape for aquariums! 2x Small portal viewers 2 pack 3.36" x 3.36" 1x Large portal viewer 5.9" x 5.9" Works in any aquariums nano, small, large, freshwater, saltwater and more!