You either breed them or buy them with coins and gems
You can't win in dragonvale, unless you consider collecting all the dragons a win.
You either need to breed new eggs in the breeding cave, or buy them in the market.
No dragons
All DragonVale hybrids are bred by picking two dragons of different elements to be bred with each other.
You can breed 2 earth dragons together or you have to spend 75 dragoncash in the eggs section of the market
There's over 1,000 types it's almost impossible to know them all!
No they are not.
No, DragonVale dragons are not able to be traded.
No, emerald dragons are not breedable with any dragon. This is true of all of the birthstone dragons.
level 10
You feed them dragon food.
The dragons in DragonVale are not trainable. You only feed them to level them up and breed them.