| | Re: Best tank under 30 gallons
As others have said, it really depends on what you're trying to do. My favorite tanks are my 2.5 gallon nanos. They can be put just about anywhere, maintenance takes little time, and I love the challenge of aquascaping something so small.
The 20 gallon long is a nice size tank. Doesn't take up much more space than a 10 gallon, but has more stocking options. Nice footprint for aquascaping, and the height makes it easy to light adequately. The 29 gallon, which has the same footprint as the 20 long, also has pleasing proportions.