I did leave the mouse overnight and took it out in the morning. Sorry for not clarifying. I think the blood was from her biting the mouse but maybe I'm wrong. I cleaned the tub in the morning too, so I don't think that she was in feeding mode. She's definitely interested because she does coil and constrict and then try and find the head. Are you sure that I should wait 1-2 weeks to feed again? Thanks.