I have a poorly platy 
She is not her normal self and has gone very thin. What is most worrying is that she is curving in on herself. I consulted Dr Google and it suggested fish tb and now I am very worried although she doesn't have lesions nor has she gone pale. I currently have her separated while i set up qt tank.
Does anyone have any idea what it could be please?
Ftr my tank is 240ltr and water parameters when checked before 20% water change today were
0
0
20
We have had no additions to the tank for quite a while. All other fish are happy and content and feeding well. The only new thing is we have been adding liquid carbon to the tank.
That is all i can think of really. Thanks guys.