What is this?

Can someone please help identify what this is on my poor dwarf gouramis' face? And is it treatable? Or should I just let it do it's thing? He is in a community tank, 36 gallon bowfront, no other agressive fish in the tank.

Water parameters are 8.0 pH, 0 ammonia, 0 nitrites, 5.0 nitrates

Can someone please help identify what this is on my poor dwarf gouramis' face? And is it treatable? Or should I just let it do it's thing? He is in a community tank, 36 gallon bowfront, no other agressive fish in the tank.

Water parameters are 8.0 pH, 0 ammonia, 0 nitrites, 5.0 nitrates