Some times it takes more than a few hours for someone with an answer to see the post.
To breed goldfish, you need fish that are ready to breed and a water temperature warming of below 60F to about 65F.
A great deal of plant matter in the tank or pond will also help keep the adults from eatting the eggs.
As well, the usual perimeters of good food, clean water, proper sized container are also important.
Breeding Goldfish is a lot of responsibility. They can lay over 2500 eggs! I suggest that you breed guppies first and get more experience and then breed Goldfish. You will need a 20 gallon spawning tank for a pair or a trio for goldfish. After they hatch you will need to move them to a much larger tank (about 55 gallon) You also need to feed goldfish fry live food. For breeding guppies move the female to a 5 gallon tank. After the frys are born move the female guppy to a 2.5 gallon tank for 1 day to regain health before you move her to the main tank. After 1 week move them to a 20 gallon.
I should start with guppies but first I need to get guppies. I have more questions now.
1.Do Goldfish and guppies go well together even though the coldwater/freshwater difference is in the way?
2.What temp. will be ok for both at the same time?
3.I have an empty 2 US gallon and a 10 US gallon Goldfish tank, where do you get breeding stuff in New Jersey(and nearby states). I know of Fish factory, BX (MIlitary store), a small pet store, and a huge Aquarium store with other pet stuff too, near a circle (made of road)
4.Should I use the 2 gallon tank for breeding (left to cycle first) or leave it alone.
5.I have no breeding experience (unless you count viritual fish). How many plants per gallon?
6. Should the male guppy be with the female guppy or not?
Guppys breed all the time they don't come into season. Guppys being livebearers don't breed the same way goldfish do. Goldfish lay eggs.
If you have an extra 10 gallon tank you might move one of your goldfish over to that tank and give them a little more room instead of buying more fish right now . The 2 G isn't really big enough to put fish in.
1. Guppys and goldfish do not go well together. Guppys prefer their water temp in th upper 70's (approx 78F) Gold fish prefer their water 65-70F
2. there isn't a temp they would both be comfortable at together.
3. See above
4.The 2 G isn't big enough for fish. Sorry
5. You really can't get too many plants, theres no need to figure plants per gallon.
6. when breeding guppys it's best to have 1 male and 2 females to keep the male from harrassing the female too much.
7.Guppys don't have a season. They breed all the time.
I'm sorry I must have mis-read #3, I thought you were saying you had a 2 gallon and a 10 gallon empty
The LFS will tell you that you can put fish in a tank that small, and will sell you the tank and fish for it and when they die they will sell you more etc. but it is not big enough for fish. It would be pretty with some plants and maybe a pretty snail.