I've only owned my discus for about 11 days but so far I haven't seen them poo. There are other fish in the tank which could be responsible for the poo I can see on the bottom of the tank. The discus are eating plenty and appear healthy. Should I do a precautionary worming?

If I do, should I do a Prazi treatment or Levamisole treatment? The only symptom I've noticed is no witnessed pooing.

Thanks