you may just be fortunate to have a laid back gourami. Since gouramis can be territorial, I'd introduce him to the new tank last- that way everybody else is a bit more acclimated to the tank while he's staking out his new territory.
I am now on my second tank.......and would tell anyone looking to buy a tank........dont start any smaller than a 29 gallon....and if you have the money/space.....start 55........Financially.........kind of dumb to start at a 10.....then go to 30........then go bigger again.........tanks, filters, hoods and stands can really add up. Especially when youve bought a whole set 3-4 times.
If you can return the 30.....do so and buy yourself a 55 ......Tank hood and stand...about 150-180. all you would need is a filter and decorations.
oh I'd love to have the 55 gallon (or more) but i live in asmall house and have to think about size. weight is also an issue, best i can calculate a 30 gal weighs about 300 lbs. a 55 would be almost 500lbs... whoa! its an old house, and my office is on the second floor, i dont want fish tanks crashing through the floor! my wife and i are looking at a bigger house in 2-3 years, so i'm gonna go 3 digits when we move someday!!! (i'll probably keep the 30 then too! 2 tanks, cool!)
I've got a 45 gallon at my place, and I live in a mobile trailer that was built in the 50's!!!!! I don't think that an older house should be too much of a problem, just place the tank neear a load-bearing wall and you'll be fine.