Betta Fish: New to fish keeping, what does this mean?

Hello everyone, I am totally new to fish keeping, but after seeing the conditions that most Betty's are kept in pet stores I decided that I wanted to "rescue" one and try to give it a better life then the one it had in a micro container.
I got a smallish tank to start and cycled it for almost a month with some live plants, a heater, a filter, etc.
I finally introduced the fish to the tank yesterday and after the first night this was in the tank.
Is this what they call a bubble nest? If so, what does it mean? Should I try and get him a female so they can reproduce? Should I just ignore it? Is it normal for a fish to do this on his first night in a new tank? Is it not a buble nest at all but something else that could harm my fish?
Sorry if this are all stupid questions, as I said I am new to this and my intentions are pure, but I am still learning.
Anyway, thanks in advance for your help