Floating Oranda

It does sound like he is suffering form a mild swimbladder problem. High
nitrates have been linked to this so it is important that you test your
water parameters (ammonia, nitrite and nitrate) as soon as you can.
STarving the fish for 3 days then feeding nothing but defrosted frozen peas,
shelled and chopped for another 3 days often does the trick for mild cases
so it would be worth a try (it wont hurt your other one to follow the same
regime). It is also a good idea to feed peas twice a week in order to keep
it from happening again.
Flakes aren't that great for goldfish - high protein sinking pellets are
generally best.
Mel.

"MartinOsirus" wrote in message
...
One of my Orandas seems to float at the top of the tank quite a bit,
especially after they eat. I'm wondering if he's gulping in air with
his
food.

Yes he's gulping air if feeding at the water surface. Feed sinking food -
pellets best for the larger fish. Pre-soak the food so it sinks. Gulping
air
can cause floating.