If you only have one fantail, then it should be in at least a 10 to 20 gallon tank alone. The tank should have a filter and either an air wand, or an air stone.
The temperature should be about 75 to 78F, and you should feed your fish only what it can eat in 1 to 2 minutes twice a day.
You will need to have a test kit to test the water, and you should do weekly water changes of at least 50%, and make sure you add water conditioner back per the instructions on the bottle at each water change.
Fantail goldfish tend to have a shape that looks as if it is bloated so firstly make sure the fish is just not the way it should be by comparing it with other fish of the same size and species. If the fish is definitely bloated and its scales are laying flat as normal, you could try adding 1 level teaspoon of Magnesium sulphate (MgSO4) per 2 gallons of water. This will act as a laxative and could free up whatever is blocking the fish from passing either poo or the fishy equivalent of wind. If the fishes scales are sticking out like a file or rasp the fish has "Dropsy" which in my experience is always a fatal disease. There are many products commercially available at pet shops that claim to cure almost everything including dropsy and usually they are very expensive. I have yet to find one that actually works on Dropsy. In this case I would advocate euthanising the fish.
The best thing is to take it to the vet they will have all the right medices that will help your fish.
Fantail goldfish are a hardy breed, strong swimmers and they compete well for food with the ryukin, shubunkin, comet or common goldfish; making these goldfish breeds good tank mates for your fantail goldfish.
yes
Female Fantail goldfish can not get pregnant they lay/scatter eggs when they are chased by males . So you have nothing to worry about.
If the goldfish is upside down and it is bloated, ................................It might be DEAD!
Yes. It may have a hard time swimming for awhile until it gets used to it. Sorry, there is no cure.
Goldfish are peacefull fish and do not normally fight with one another.
it has a short tail
Yes, but slowly.
A fantail goldfish can be any of the goldfish colours which can include any or all of the following white, gold, silver, copper, blue, orange etc etc.
Survival of the fittest
They are both goldfish and so can breed with one another if they are of different sexes.
suma nimo