It needs to be atleast 2 ft deep if you want to keep the fish in the cold weather however i would suggest going much deeper to be on the safe size, a small pond can have steep sides to dig to about 3 ft and there will be no problems with the fish in cold weather, other than that it is not important how deep the pond is, as long as they can swim freely.
It depends on where the fish pond will be. It can technically be as deep as you want or as shallow as you want. I would suggest you make it at least 1/2 foot deep. If the fish in this pond are to survive the ice and snow of winter, the pond should be much deeper so the fish don't die of the cold/get frozen in the ice. The circumstances will effect how deep you should make your fishpond.
Either a tank or pond of at least 30 gallons is a suitable environment for a goldfish.
Goldfish need plenty of room to swim around and get very large. In a 1000 gallon pond you could put 25-50 goldfish just keep in mind that goldfish grow very large and need about 20-30 gallons each when full grown.
pond
yes
The goldfish will eat the mosquito's larvae before they can leave the pond and fly.
How large is large? Ideally they need either wide and long tanks, or a large established pond. The general rule is Fancy Goldfish need a minimum of 20 US gallons each, Common/Comet type Goldfish need 55 US gallons each, as they get larger and tend to be more active and capable swimmers. Their tank should be very well filtered too! For a pond it needs to be filtered and over 600 US gallons, a minimum of 3ft deep at the deepest point.
A swordtail is a tropical fish and a goldfish is not. The swordtail would need a higher temp. than the goldfish. Depending on where you live it probably wouldn't survive the winter.
This is a literature question not a goldfish one.
no the goldfish would it the tadpole
goldfish
It may depend on what other animals and plants you have in your pond. You may want to feed them so they have the correct nutrients they need.
Year round, but especially in Spring for pond goldfish.