Rainbow Fish Lip Growth?

Hello, I am new to fish keeping and this is my first post here

I don't think its an emergency as such (but it seemed like the most logical place to post), but my Female red rainbow fish has what appears to be a white growth of some kind on her lip.

I recently treated the entire tank for whitespot which seemed to work very successfully, and now none of my fish have whitespot but she still has this same problem

It doesn't appear to bother her, and aside from that and a recent tail nibbling from a feisty puffer fish she is in very good health along with the rest of my fishy friends. In fact I've only lost one fish since I started my new hobby and my recent water test came back with trace or no nitrates, nitrates and ammonia

I've attached the best picture I could manage, I think she is camera shy!

Hope someone knows what this is

Thanks

Sorry I missed this bit -

Tank size: 100 litres
pH: neutral
ammonia: 0
nitrite: trace
nitrate: trace
kH: local water here is quite hard
gH: not sure what this denotes sorry
tank temp: 26/27 degrees celcius

Fish Symptoms (include full description including lesion, color, location, fish behavior): none apart from white spot on her lip (about 1mm)

Volume and Frequency of water changes: I have been doing 10% water changes every 2-3 days since i introduced fish as the nitrate/trites shot up

Chemical Additives or Media in your tank: Fluval internal power filter

Tank inhabitants: 6 rosy tetras, 6 neon rainbow, 2 red rainbow, 2 golden panchax, 4 corydoras, 2 khuli loaches and 2 dwarf puffers

Recent additions to your tank (living or decoration): the golden panchax (but the problem has been apparent for a week or two)

Exposure to chemicals:

Digital photo (include if possible): attached

Mouth fungus columnaris, myxazin by waterlife and pimafix.

Wilder said:

Mouth fungus columnaris, myxazin by waterlife and pimafix.

Click to expand...

Great thanks, is this common and is there an easily available treatment from my lfs ?

mixazin + pimafix - got it tyvm : )

Don't be too hasty. Rainbow fish are notorious for getting harmless growths on their lips. You may be medicating with no result. Unless you are sure that you can see visible woolly fungus or an open wound. I even spoke to my very knowledgeable lfs and they say it often appears on the older fish. Not generally juvis. I'm not sure if it's because they swim so fast and shoot up and hit the inside of the lid (my reds used to do this very often). And thus sustain damage to their lips. Could you get a clearer pic?