Growth/bubble/something on my Daemon, what could it be?

[cvc85]

Hey all, I picked up a batch of young Daemons a couple of weeks ago.

Background of the QT. During the QT i noticed bumps on some of them. I have encountered identical bumps before on a batch of mesonauta i bought early last year from the same shop and though i never found out what they are exactly(some translucent egg sack looking thing), i do know they are not lice(cos i dose parazin as part of my qt) and its not contagious and they can be removed safely by manually scraping them off. I did that for the affected daemons and let them heal up. After that the last 9 days of QT was smooth and uneventful and i put them into my main tank today. The transfer involved 40mins of acclimatization and the fish were happily sifting and unstressed within an hour or so.

After i got back from work(~7hrs later) i noticed this bubble on one of them. The best way i can describe it is literally a bubble, as you can see from the pics. Can anyone help me with a diagnosis? I doubt it's gas bubble disease cos the location of the bubble is not typical of gas bubble disease and my water changes are conducted via the sump, so the water has plenty of time to 'degas'.

Any input is appreciated!

Cheers