Do my discus have Hex?

[broadfoot]

I first suspected my discus of having worms because they weren't pooing, and it seemed like the spit out a high proportion of their food. So I've dosed them once with Prazi (next dose due this Wednesday). However none of them expelled any worms.

I dosed 1 tbsp / 10 gallons of epsom salts to see if they were constipated, still no poo.

Today just after feeding some beefheart I saw one of my fish had something white and strange hanging out if its anus, here's a pic:
http://farm9.staticflickr.com/8053/8084209112_72014fc4b6_b.jpg

My situation seems to fit a description of Hex from this info page http://www.discusnews.com/article/cat-02/spironucleus.shtml

The description is: "Severe case or reoccurrence - This is where the Spironucleus has not been spotted early i.e. the discus has demonstrated a behavioural change indicative; white poo may have been seen on several occasions and the fish may in fact no longer be passing visible excreta."

Because I can't see my fish pooing, and I've seen this weird thing on another fish (in my picture) I'm thinking they might have Hex.

Can anyone confirm or deny it?

I'm planning on treating them for it anyway, just in case.

Thanks