Thanks Richard.

I emailed The crew at wet web media and this was their response.

<Yes, I'm afraid
so... nematodes and cestodes are the most common culprit - like
tapeworms, they can out-compete for nutrients.>

<Do try to get ahold of some febendazole from your local veterinarian.
Your best bet is to put this fish in quarantine for about three weeks
and treat the quarantine tank directly with the febendazole for that
entire time. The Noga book of Fish Disease recommends 2mg/liter or
7.6mg/gallon of tank water. This should give your fish the upper hand against
these parasites.
Cheers, J -- >

I just hope my main reef doesn't catch this parasite.