Goldfish commonly grow to over 12 inches. The size of your tank would indicate that it is not really large enough for keeping goldfish in. The basic rule of fishkeeping is "1 Inch of fish needs a minimum of 1 gallon of water. Goldfish should really be kept in a pond.
No. A 10 gallon tank is barely big enough to keep a single goldfish in.
Goldfish grow extremely large; fancies will become fatter, and singletails grow quite long. You should only have 2 fancies in a 30 gallon, or one singletail for proper health and growth.
you will need a gallon for every inch the shubunkins grow you will need at least one gallon for a snail
it depends on how big it is if it is a goldfish or beta it can be in a bowl.If it is one of those big tiger fish or aqarium fish then put it in a big tank. A fish will grow to the size of the tank or bowl. For instance, say a goldfish is in a tank, it will not grow as big as the tank; however it will grow big enough to be able to swim in their environment. The fish will not overgrow the tank. I had a six inch goldfish in a thirty gallon tank.
It depends how big they are if they are still small yes and as long as they are not 3 inch's or more yes.
Absolutely not! Unless the goldfish is half an inch and going to stay that way you are seriously hurting your fish! A comet goldfish will get very big! you need at least a 55 gallon tank for that sucker! Try raising a smaller regular goldfish in a 20 gallon tank. You'd be far better off!
Yes, the bigger tank the better. They actually HATE goldfish bowls. (they're not nearly big enough). Goldfish usually need a 20 to 30 gallon tank
For twenty small (1-1.5 inch) Goldfish you should have something like a 30 gallon aquarium.
yes
about 10 or 15 depends on how big they are
No it will not. It will be runted by the lack of room. In order for goldfish to grow to full size they should be housed in ponds or very large aquaria.