Angel with blister?

[becs66]

Hi,

I was wondering if anyone could help diagnosing my angel fish. Overnight he has developed what looks very much like a blister you or I would get on the top of his head. Its about 4-5mm in diameter and about 3mm raised from the surrounding skin and translucent white. He seems absolutely fine in himself and eating well. He is in a well established (nearly 2 years) 35gal heavily planted tank with ammonia 0, NO2 0 and NO3 near nothing. No recent changes to the tank have been made and I perform 20-25% weekly water changes.

Thanks!

Becs

 

[becs66]

Anyone???

 

[Doggfather]

hmm, not sure what it could be.

my angelfish once had a small blister on it's underside, which eventually popped and his breeding organ appeared for the first time...but if it's on top of it's head i don't know what it could be, maybe a micro-organsim of some sort? maybe it will eventually heal over time