HELP! Gourami looks like it has a chunk biten out of him or is it a disease?. Not house with any aggressive fish just 2 other angel fish, 2 other gouramis one dwarf one pearl. 3 rosey barbs and 4 corydoras. I know his fins has been nipped at before but nothing this serious. He is still eating and acting fairly normal. But read some threads online that concerned me about a few diseases. Any input? thanks!