This 4" x 2" Rectangle Moss Ledge is great for shrimp and betta tanks! Shrimp love to forage and hang out on it and Betta's love to rest on it almost like its a bed or hammock. The suction cup versions of these fail over time and wont stick on the glass, that's why we designed this to have strong embedded magnets to hold our moss ledge up and stay up. Use fishing line to tie on a portion of moss, then position it in your aquarium where ever you like and watch it grow! Moss not included.