Hi all I am a newbie here. I just picked up a couple of pond snails at my LFS and
they have what looks like dark green algee or moss on there shells. What the heck is this and are they safe? :o

sounds like algae. i have seen 2 eat it off of eachother so maybe they will. it shouldnt cause any problems, may introduce it to your tank (im assuming you didnt add them to a pond this late in the year, if you are in the U.S.).

Algae will often grow on snail shells. It shouldn't harm them. With big snails, you can sometimes use a soft toothbrush to remove some of it. Pond snails are too small to clean unless as Reptile Guy said, another snail does the cleaning.

For me, the concern is more about introducing perhaps another species of algae to a tank or pond with the addition of an algae-covered snail. Lately, the Japanese trapdoor snails that I get to put in my pond each year have hair algae (mossy-like) really bad.

do you have plants in your tank? did you buy the pond snails?

my apple / mystery snail has algae growing on hes shell and it dosnt do any harm :D