Project--The responsible but cool stock 12g DX??

[Mummer]

Please do weigh in on this.

 

You have a stock 12 G Nano Cube DX (48 watts of lighting). You do not want to do anything with the lighting. You are willing to upgrade the stock pump and add a heater. You are also willing to remove or rearrange the sponges, bioballs and so forth in the rear, and to add third party filter media. You will of course monitor salinity, ammonia, nitrites, nitrates, PH and temp and you will do regular water changes with high quality RO water. BUT, you do not want to mess with worrying about iodine or calcium levels and the like.

 

You don't want just a tank full of snails and little hermit crabs.

 

Given these parameters, please describe the coolest/most unusual livestock you would keep.