tHEcONCH has just taken down his 8 litre nano because although he found it technically possible, it was a suprising amount of work to keep it healthy which made it a lot less fun than his main tank. The biggest problem was maintaining a stable temperature - even in tHEcONCH's fish room which stays pretty much the same temperature all the time, the nano's temperature still swung 7-8 degrees - tHEcONCH thinks that is because the smallest heater he could get was still too powerful for the volume of water, and the thermostat was too slow to react.
That said, tHEcONCH kept small frags of zooanthid, sarcophyton, discosoma, Xenia, and Pachyclavularia in addition to the usual compliment of snails, starfish, etc. Most of those frags are now available at your favourite fish shop (bottom tank).