I saw some Mountain shrimp for sale im a lfs, just wondering if any one had some info they could share. like how big they get, if they fit in with community fish and feeding habbits. Any help would be greatfully recived.
Check out some of the profiles and pictures of "mountain shrimp" on the net and make sure that is what they have. From what I've seen there may be several species called "mountain shrimp" and many stores are also notorious for mislabeling shrimp so double/triple check that you are getting what you think you are buying. See if they can give you the scientific name of what they think they bought.
Mountain shrimp is usually another name for Bamboo Shrimp (Atyopsis Moluccensis) -- and incidentally, they're usually a darker colour than the one in that photograph. If this is the case, they should be easily recognisable by having a pair of brush-like fans instead of claws. Fan shrimp like these are filter feeders, so it' recommended you don't buy one unless your tank's been established for at least 6 months (to allow time for all the bacteria and infusoria they eat to build up). Alternatively you could target feed, but this is tricky and not always sufficient.
Of course, this is assuming "Mountain Shrimp" is what I think it is. If it's not like the one in that link, can you remember what it looked like?