If, by air gulping, you mean, going to the surface once in a while to get air, then yes, that is perfectly normal. They have rudimentary lungs. If they are constantly going up for air, that could mean there isn't enough oxygen in the water or the parameters are way off.
Water parameters: Are you checking your water parameters regularly to make sure you have 0 ammonia, 0 nitrites and low nitrates (under 40 ppm)? Is your temperature low enough (in the 60's F)?
I'm not sure what you mean about having a grip on glass. They have a hard time walking on glass, like in a bare bottom tank, but it isn't a problem. They still get where they are going. :happy: