Oranda headgrowth falling off

Question
I recently lost a calico goldfish to what I believe was dropsy.  I now have an oranda and another fancy goldfish left in a 29 gal fish tank.  The orandas headgrowth recently had a black spot above his eye, then another one started above his other eye.  Now the headgrowth is "falling off?" leaving a white spot.  I've checked the water and all seems normal.  His activity seems normal; he's not hiding out and he seems to be eating fine.  Will he lose all of his head growth?  Do I need to worry about the other fish contracting something?

Answer
Hello "P"-

I've heard of orandas losing their "top knots" before, and it seems to just happen randomly, even if the water conditions are fine.

The black spots, however, are usually a sign of infection, like fin and body rot. Perhaps a slight infection caused the top knot to fall off?

You can add Melafix to the water, to promote regrowth of the top knot. I haven't owned orandas before, so I couldn't say if it will regrow fully.

The white spot is the equivalent of a scab, and should eventually heal to a normal color, if it doesn't grow back.

I would add some aquarium salt and a dose of QuickCure to the tank, just to prevent any possible reinfections.

Hopefully, all should be well.
Hope this is helpful!
-Amber Worman