Could be hex...but Im not an expert. I would turn up the temp to 85 degrees add aquarium salt, and do water changes every couple days to keep the water clean. Add more salt every time you change the water.....Hexamita
Symptoms: The first symptom of slimy, white mucous feces, even while still eating and acting normal. Further signs are the fish hiding in the corner it's head down, head above the eyes gets thin, they blacken in color, and swim backwards.
Hexamita are intestinal flagellated protozoa that attack the lower intestine. Discus and other large cichlids, especially Oscars, are especially prone to Hexamita. As it is a disease of the digestive tract, a wasting away or loss of appetite may be experienced.An effective treatment is the drug metronidazole. A combined treatment in the food (1% in any food the fish will eat) and in the water (12 mg per liter) is recommended. Repeat the water treatment every other day for three treatments.