The silver dragon is a treasure dragon, and they are a little more difficult to breed than some other dragons. Just keep at it. Some successful methods are:
Iceberg + Steel (reportedly the most successful at about 14%)
Steel + Storm
Cold + Mine
Cold + Metal
ironwood dragon and storm dragon
If you breed any type of dragon as long as they are lv 10 you will get them
You don't breed a Kairos Dragon in DragonVale. You have to get parts to complete it.
U breed the two dragons ice and sandstorm
you breed a ice dragon with a mine dragon
You have to breed a plant and a fire dragon.
As of July 2012, there has not been a star dragon in DragonVale.
You have to breed a sun and moon dragon together
You have to breed a metal and a water dragon together.
You have to breed a plasma dragon with a salamander dragon.
Breed mine( cold and metal) with cold and you may get it Add me on game centre : blue zebra world
There is no "marsh" dragon in dragonvale but if you are referring to the moss dragon the best way to get it is earth and plant, although you also have a chance to breed the tree dragon.