Worried Discus might have worms

Hi everyone,

I purchased 6 Discus about 5 weeks ago in my 75 gallon aquarium. Everything in the tanks is going well; the chemistry is good (pH: 6.5, hardness: 25, Nitrate: 5, carbonate: 20) and all fish are growing fast and healthy. But one discus, pictured below, seems to be a little skinnier, is often picked on, and turns almost black in some light. It naturally looks much darker and closer to a wild discus than the others so I am mostly worried about it being skinny. It eats a lot-- as much as the others but it still seems to be the most reclusive and scrawny. Do you think it is possibly dealing with worms? The pet store I bought them is quite trustworthy in my experience and claims all have been throughout dewormed and tank-bred.

Thanks, all feed back appreciated!

if the others weren't doing so well, I wouldn't notice anything about him, but I just wanted to make sure he is ok before he potentially gets worse

maybe put him in the quarantine 20g.
to ensure that the worms will not be passed on
i reccomend @Colin_T's way of soaking fish food in medication...
ill notify you when i find th elink

Sometimes a group of discus will pick on the weakest link. They can be like birds for that. That fish is of a poor shape, and isn't in good health. It may never have been.

Tank bred fish can be a problem, but deworming is very easy and unless the breeder is not very skilled, they probably are dewormed.

If I move him to the quarantine, do you think the stress level of being alone and in a new environment could potentially be more risky to his health? I have had some fish die when I move them to quarantine, but usually because they were already in life-threatening condition. Do you think the discus could take it?

Thanks for the feedback, any help appreciated