There may be a water quality issue in your tank. Make sure that you are testing for ammonia, nitrites and nitrates which should be 0, 0, and less than 10 respectively.
If you have readings of ammonia or nitrites, or a high reading of nitrates, you should do an immediate 75% water change. Make sure that the new water you add to the tank is the same temperature as the old water, and be sure to add the correct dosage of water conditioner per the directions on the bottle.
In addition, check the PH of your tank - it should be 7.2 to 7.6 for your goldfish; if it's too low, it could also affect your fish, and the water change should help that as well.
If the goldfish is swimming in water, it is alive.
Swim bladder disease? http://www.straightdope.com/columns/read/1688/if-a-goldfish-is-swimming-on-its-side-is-this-a-bad-sign
Yes
it stops swimming
No!
Gravity
if it is not swimming and it lays on its side then it is dead.
Some ways you can tell that your goldfish is sick are that it might start swimming slowly, upside down, sideways and around in circles. Its colour might get patchy or blotchy and its eyes might look cloudy and close a little bit. It might also go to a corner of the tank and just sit there for long periods of time.
It's not swimming. It's dead. Sorry :(
Stop doing a handstand. If your goldfish is floating, it will float to the top, not the bottom, therefore, you must be upside down!
The fins develop on a goldfish fry after about a couple days after they are hatched. Until then, they are not free swimming and look like a tadpole.
Probably because its water is foul and needs changing