At one time in 1998, I had 5 tanks going at once, ranging from 20 gal. to 55 gal. The smaller the tank, the harder it is to keep clean! I also found out that one angry pleco can smack a small rock into the side of the tank and break it... and that a 37 gal. tank will put 2" of water on the entire floor of a 12x24 floor in a matter of seconds! <sigh> Not so much fun to clean up and try to save the fish. Right now, we only have room for a 20 gal. in this house and I'm about ready to give it up because of algae problems that just won't stop. Take my word for it - start with a 55 gal. or higher and you'll enjoy it more!
I wonder, sometimes, if we ever give God a headache.