At first my Kaoru pecked at it, then rubbed all over it, then after nearly balding part of it she made a nest out of it. THEN she learned it moves. Now she's still a tiny betta but rapidly growing so getting it to move takes a bit of effort. She'll wedge between the glass gems and marimo till it moves. She has gotten the Marimo to roll on her already-really no idea how, but thankfully she got free by herself so not really concerned about that to much. To her the marimo is a toy, a bed, and sometimes food.