A few nights ago one of my Gold Gouramies starting doing the same sort of thing - I only noticed because she was headbutting the thermometer which would then clink against the glass of the tank! She constantly did it all night - then I noticed the other fish - mainly the two Swordfish - were pecking at her, not just chasing but actually pecking at her skin/scales parts of which were staring to turn red. She didn't have the energy to chase them away so I rescued her, put her into a breeding cage, and dropped a few drops of Antiseptic straight onto the red parts of her body - I did this twice and then yesterday let her out and she seems fine once again.