Sick oscar :(

[Shane87]

Hi my tiger Oscar has been sick the last few days . He seems to feel better just a bit lethargic but then acts sick again like just laying on the bottom, breathing heavy and not eating, The only thing I have noticed is a small scratch on his side, a slight tear to his left pectoral fin and very white stringy poop there constantly ( in attached picture) since he has been sick. Any ideas?

 

[Shane87]

Water perameters are fine after I just checked them again, exactly the same as when I 1st tested.

Ammonia 0.0ppm
Nitrate 0.0ppm
Nitrite 0.5 ppm
Ph 7.0