I'm sorry to hear your fish si having this problem. Unfortunately, in the fancy goldfish (because of that egg-shaped body) swim bladder problems are common, and once they occur, they are likely to come back time after time. For that reason, fancy goldfish often don't do well in ponds. The swim bladder is an organ that enables the fish to properly orient itself in the water. When something goes wrong, the fish may float, swim upside down, or at an angle. The best thing to do would be to bring the fish inside for the winter. You'd need to set up a tank using water from the pond so there wouldn't be a sudden temperature change. After the tank warmed a bit, there are a couple of things that may help the ailing fish. If it will eat, give it a couple of thawed out and peeled frozen peas. If the peas are too large, you can smash them between your fingers before putting them in. You might have to hold them right in front of his mouth. You can also add one teaspoon of aquarium salt per gallon of water. Keep feeding nothing but the peas for a few days. Here is a link with other ideas for treatment and more information:www.netpets.org/fish/reference/freshref/swimbldr.html
If you must leave the fish in the pond, don't feed him anything. Feeding pond fish in cold weather can bring on problems like swim bladder disorder. Unless you want to call an aquatic vet, the salt will be the main thing you can d o for a pond fish at this time of year. There is a needle method often used by vets. You have to know exactly where the swim bladder is and put the needle right there. If you do it the wrong way, you're likely to kill the fish. I have never done this, and don't recommend it. It doesn't cure the problem, but temporarily 'fixes' it. It's likely to occur again. there's a little more about it on this site:http://www.netpets.org/fish/reference/freshref/swimbldr.html
If you want to consult a vet, this link will take you to a directory of fish vets:http://www.aquavetmed.info/index.cfm?PID=6
Your best chance of helping the fish without a vet would be to bring him inside. If you have more questions, let me know by clicking on REPLY. I hope your fish will recover.
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