My flowerhorn look sick!!!

[aykinhk]

Hi , I found my flowerhorn looks sick
He alway stay at the bottom of the tank not moving all the time when light off , but when I light on ,he swim up to the top ,light off down again .
Also I look at his front face looks like a but skin off. Anyone has ideas
I will upload some photos later tidayb

 

[aykinhk]

His poop is not white , just as normal
Temp is 26c I do 50% WC every 5 days

 

[kno4te]

Would post ur water parameters. Make sure there’s some decor and plants in the tank.