Orandas - sick?

Question
We have a large outdoor concrete pond (about 7500
gal).  In it we have a variety of fantail goldfish including two lovely orandas about 4"
(body) plus 4" or more of tail.  One has been
floating upside down quite a lot over the last
two months.  I have isolated it in a screened
plastic crate on a shelf in the pond with water
lettuce.  It seems able to hold itself upright
for only short periods of time.  Then it either
bellies up or hangs nose down in water.  Is
this behavior due to usually overdeveloped body
type?  We have had much problem with green algae and are awaiting shipment of algae killer.  We
do pump fresh water (about 25%) once or twice
a week.  (We are on well water.)  The other oranda seems fine.  Thanks for any insight.  

Answer
Hello Bob-

I apologize in advance, I don't have much experience with pond setups. However, this swimming problem probably stems from a swim bladder anomaly - Most commonly this is caused when the fish gets bloated and the stomach presses on the swim bladder. To help relieve your fish, you can try fasting him for a week, and feeding him only defrosted peas. The peas help regulate digestion, and will hopefully "clean him out" so that he can swim normally. Swim bladder troubles are not painful to the fish, are usually not contagious, and fish can live normally for quite some time if the problem is not resolved.

Hope this is helpful!
-Amber Worman