It's a difficult she could just be stressed out try turning down the lights add more cover some extra apisto caves offer some live or frozen foods to see if she will eat add a small amount of aquarium salt 1 table spoon for 5 gallons that shouldn't harm your plants and will aid Gill function and add essential electrolytes to help reduce stress in your fish I would recommend Qarantineing any new fish in future for minimum of 4weeks if your seeing no improvement after after a few days or she gets worse I would treat with the praziquantel and metronidazole if you have some left as metronidazole treats anaerobic bacteria