Very pretty! I like the big rock in there too!
I was wondering if anubias might be a better choice as far as plants go....not too many fish will eat them! Don't get me wrong, I love sword plants but I do know that they can be shredded fairly easily....and goldfish are notorious for chewing up plants.
Since you already have an established tank, you could easily jump start the 3g by putting live plants in there, add some of the gravel from the main tank, and adding the large rock or other decor from your 12g to the 3g as a temporary measure.....leave the rock/decor in there for a couple of weeks for the bacteria to establish themselves elsewhere......you can put the small fish in there right away doing that. (It is ALWAYS a good idea to keep an eye on any jump started tank and do a water change if the fish act or look sick.) I've started several tanks using this method without any problems.
BTW, if you decide to jump the small tank, don't clean the filter on the main tank until you get the rock or other decor back in there, or wait at least a 2 weeks for the bacteria to get it's population back up within the tank, just to be on the safe side.
After I posted this, I thought I better clear something up! Whatever you do, don't remove the plants from the 12g AND the rock unless you are replacing the plants.....you don't want to disturb the main tank TOO much....know what I mean?
