Honking, snoring sounds, head shaking, sneezing, watery white stools

[twinstwice]

My 4 month old golden comet was fine yesterday and woke up today with all this nonsense going on. She was still pecking around and hanging with the others, so her attitude is still good. The other 3 girls are still behaving normally. I've quarantined her but am at a loss as to what the cause is. I see no gape worms in the throat but not ruling it out entirely. any advice/help would be much appreciated.