Do you know how warm the mouse is when you introduce it to Rockie? That is the main thing (imo) that confuses a snake about f/t. I have almost 30 ball pythons, and every single one of them takes f/t rats without hesitation- as long as I do it right. The water they are in MUST be over 105F. I don't know why. If the rat is right at 100F, the snake won't even look at it. So, maybe you can try that if the water wasn't hot enough. And patience is usually the key with these guys. Especially when making the switch to f/t. Sometimes my best feeders still take 8-10 minutes to even look interested (and by that time my arm is getting pretty tired, lol). But eventually they take it.

Oh, also, how exactly do you offer it? You can try to take the mouse by the scruff of the neck and make it look alive by prancing it around the floor of the enclosure. This is what I have to do sometimes, and it works 9 times out of 10.

Good luck,
Jennifer