I kept the pair of clowns and RBTA that Ace has at school rignt now in an 8 gallon nano for over 2 years. All stock, except that I used no bioballs and I instead used the blue & white filter material. Added a small heater. It has 3 x 8w T5s on it.

The tank was heavily planted with razor caulerpa.
I changed about 50-60% of the water every couple of weeks. I hate to say this, but I didn't even worry about matching the temp - I just dumped it in. Those guys THRIVED in the tank.

Not saying what I did was right, but it worked...