Can i fight whit it?

I Will post u over here the pic of the water parameters, Just i change water today, well i got ready to use entizol and bactopur direct, but i still hope its just about water. I made every Day 20% but i didnt see it anything change for good mode. Maybe it need more time, just dont wanna lose him.

All other fish are Fine, i Have already bought sera bactopur direct, i was agree it can be by bad water, but i now change almost 20% every Day

L330 was there 2 years before Suttoni

Hi guys, its not going better, this photo is from today morning

Ok, thanks to all, ill let z know

Ok guys, so u think its just by bad water? Well ill do it now change
+- 20% of tank everyday, after ill start to make every 3 - 4 days +- 25% of tank. He is still eating so i hope he will be ok, díky i have to add some minerals or vitamins?

50%? Isnt to much? Ok ill try that, so u think its by bad water?

Pic of my tank

Tank size are 700L there is 6x WF Geophagus abalios, 2x geophagus megasema, 3x camopiensis, 2x Heros rokteil, PLECOS : A. Adonis, l018, l177, l330 and Suttoni , i have 2 external filters Fx6 and atman cf 1200, fx6 is now 1 month, before was fluval 304, i change 20% of tank every 2-3 weeks, pH is ...

One more detail photo

Hi guys, anyone have experience of this disease? Is it just bad water or what? Friends told me just keep feeding and change water every 7 days up to 20 %
Or should i use something to help him?

Hi guys, i rly need Help i rly dont know how to help him, my friends told me that he need just keep feeding and change water every 7 days up to 20% of tank size. I never sawg something like that, u think its by bad water?