The easy answer is Yes.
I have several in 6 gallon Eclipse tanks, trying to figure out where i am going to set up my mantis condos.
I am, however, very vigilant about water changes, uneaten food, etc...
the smaller the tank, the more you have to keep an eye on things.
If you can go a little bigger, it would be better for you, as well as for the mantis.
As far as species goes, I have the following in 6 Eclipses: G. viridis, about 3" long, G. platysoma, same size, a 3" G. chiraga, though she is moving into a 12 very soon. I also have a small P. cilata in a hex 5, but it will be moving soon as well.
An N. wennerae, perhaps a small G. smithii, a G. viridis. Have a look at Dr. Roy's site (Stickied to this Forum above), and he has recommended species/tank size suggestions.
-Ron