if you have a rubbermaid lying around maybe take her out of the tank, and leave her in the rubber maid for a day or so, as if you were moving her. make sure it's filtered and heated of course! and then add the new fish first into the tank like an hr. or two, make sure to rearrange the tank enough so that it's almost like brand new, even adding pvc pipes, clay pots, and stuff for territorial purposes, then add her last. No promises though just an idea/trick that may work for your situation. Goodluck!