Kept Oranda's for a few years - they are a nightmare.
1.They are bred to have the shortest fatest body possible = all internal
organs are crushed.
2.They are prone to take in a lot of air when feeding especially if you use
flake food.
3.Keeping any fish in a tank without filtration is asking for trouble - you may
get by with a bog standard goldfish but not these ones.
Tips for Swim bladder include Peas,Epson Salts (drop a crystal in
front and try to get it to eat it) try decent size bits of worms with bits of
mud on them this will help clean them out so to speak.
Another tip is to reduce the amount of water in your tank as this will help
with the stability (pressure).
Following the thread and with my own experiance you will probably lose
these fish as the fungus is just happening because your fish are run down.
It has probably been a internal parisitic infection affecting the swim bladder - you then start getting fungus and eventually the dreaded dropsy will make an apperance.If you look down on them the scales start to come away from the body and look like a pine cone - this is caused with the higher internal pressure and fluid retention and internal organs breaking down.The eyes will also start to bulge out again with the internal pressure.
If you plan to get more you will need to research so that the water quality is
perfect.This includes testing for Nitrate,ammonia,nitrite,PH etc the water
also need to be around the same temp when doing water changes and also
conditioning the water is vital.
If you need any info / help with this just give let me know.
I used to travel from Scotland to Birmingham to buy these and have paid up
to £80.00 for some of them.
I wish you luck with your fish - also dont go throwing all sorts of chemicals
into your water.
Could you have a look at them and give an update and I will try to help a bit
more.