Intestinal parasite?

[Renee C.]

• pH 8
• Nitrates 10-20
• Hardness 100ppm
• Nitrite 0
• Ammonia 0
• KH/Buffer 300ppm
• Water Temperature 75

Platy fish went through med trio during quarantine in August, but I have been noticing white with clear segment stringy poop. Fins are in rough shape, no one picking on him, and he seems to be eating normally. Have been feeding a lot of extreme krill flake, and blood worms to this tank. No new fish in tank. 
 

I have attached pictures, please let me know what you think:

 

[Colu]

Have you notice any rapid breathing hanging near the surface listlessness sunken belly's spitting food out @Renee C.