My protomelias taenolatus is not eating

[famulan]

hi all,

i am new to cichlids i haveone problem .My protomelias taenolatus (Red empress) is not eating for about 2 weeks under the mouth looks swollen sometimes it sits in the corner alone it has been harrassed by aan aulonocarra OB (marbled peacock its very dominant)i do water changes fortnighty i use rainwater form our watertank the water is very cold(12degs) so i heat it up to correct temp i use Prime and cycle. all fish occasianly scraqpe the bodies. i monitor PH Nitrite and amonia daily. i try to give them a variety of foods eg:flakes, flies,garden worms pellets ,frozen dinners, peas and spinach they all love the food ecept for my red empress

can anyone help Please??

thanks