Rainbow Fish

[Angiey]

Hi Folks. Can any one help me. I have rainbow fish and two of them are boesmanis. They have recently developed what looks like their lips having a growth on them. The rest of their bodies are ok and my cories, zebras are ok but this actually looks as if the top of their lips are starting to rot!! Can anyone point me in the right direction.
Many Thanks.
180 litre juwel tank. Amonia, nitrite and nitrate ok. I did have a slight spike of nitrate a couple of weeks ago but levels ok now. Less than 40.

 

[DarkEntity]

What are the exact stats just now, as "all stats are ok" doesnt really count

 

[Mikaila31]

Sounds like either mouth rot or Columnaris .

 

[DarkEntity]

Ive kept Boesmans and they were forever damaging their mouths on the gravel/wood etc in their frenzy for food. Pictures and water stats would be helpfull