sick axie please help!

I've had my three leucistic male axies, Harvey, Henry and Harry (they looked so proud when babies they got grand names) for 5 years with no problems but two days ago noticed Harvey was floating at the top of the tank and pretty distressed. The other two seemed fine so I just cleaned out the tank and put Harvey in very shallow water and he seemed to improve and be sitting on the bottom of the little tank for the day. However, yesterday morning when I woke up he was floating again and I noticed a white whispy fungus coming from his mouth. I swear it wasn't there the day before. His gills are also very, very white but I can't spot any blobs or whisps of fungus, but I guess it could be there. I used Myxazin and have put him in the fridge but as yet, no improvements and he's not eating. He doesn't appear to have fungus anywhere else on him and the other two remain fine. His floating seems to have gone again today but I'm really worried about his fungus. I haven't yet tried salt baths as his gills look so white and I'm worried about it affecting them.
Any advice would be welcome!
Thank you,
Esther

have you tried fridging him?

yes, he's been in the fridge since this morning, so about 6 hours now. No change as yet. Thanks though.

Hi Esther,

Could he have something stuck in his mouth? Is there someone who can help hold him while you to look inside?

-Eva