If she’s eating fish, she’s literally killing animals. I don’t know what failure of biology class happened, but fish are also animals, and the fishing industry kills several many animals that never make it onto your plate due to bycatch being discarded. For every fish you do eat, many more are thrown overboard as trash.

Call an exterminator and sort this shit out. It’s a health hazard, and your landlord will pay for it to get taken care of. Save the cognitive dissonance for something else.