White patches on gills of bn pleco

[Zachariah987]

I am still baffled at what this could be. Two white patches on pleco. Symmetrical on both sides.

Was not there before

No new fish added

 

I posted this on here yesterday under diseases and got one reply that it is normal when they are threatened 

 

I can't find anything on the Google website

Please help

[Guppysnail]

I don’t know what you mean by the fish being threatened?  Is something picking on him?  It could be a stress response. Most often when things appear that are symmetrical it is a natural occurrence. It could be bristles growing in.  It could be the bn flaring the side whiskers because it feels threatened. Possibly irritated from the new growth. I personally would just watch and wait. 
here is my bn dad flaring cheek whiskers to defend his cave. 

Edited October 4, 2022 by Guppysnail