An upside down fish is a classic sign of swim bladder disorder. Peas should solve the problem. All swim bladder disorder is, is the digestive tract gets full because of constipation and the digestive tract pushes on the swim bladder which is used for buoyancy. That's why the fish has trouble swimming upright.

Try that, and let me know how things are going. Also, good luck with your case of ick. I hope your fish make it.
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Phishie

"An ounce of prevention is worth a pound of cure."