I'm setting up a 29 gallon biocube HQI, now I have lots of tanks laying around (20 gallon talls and 10 gallons). I wanted the tank to be able to fit under the Biocube which has a shelf size of 18.5in by 18.5in so neither of these tanks will work under the tank. The only standard tank which would fit under my biocube would be a 5.5 gallon (I'm pretty certain that this would be way too small, correct me if I'm wrong [I don't currently own one but I could buy one]). So the question is whether or not to go with the 10 gallon tank or the 20 gallon tank, I will be leaving this tank setup with a damsel or something in it once the tank is full of fish just in case. I'm getting [ame="http://www.amazon.com/gp/product/B000260FUW/ref=ox_sc_act_title_1?ie=UTF8&m=ATVPDKIKX0DER"]Amazon.com: AquaClear 70 Power Filter - 110 V, UL Listed (Includes AquaClear 70 Carbon, AquaClear 70 Foam & AquaClear 70 BioMax: Pet Supplies@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41Rr1kpTVOL.@@AMEPARAM@@41Rr1kpTVOL[/ame] . This will work for all of the tanks mentioned, so which tank should I use for quarantine?