My first fish tank was an 11L Nano Tank in which I kept tetras and snails for quite a number of years, I then decided to upgrade.
I bought a 30L tank which, surprisingly, took a lot more effort to keep going and I had a lot of failures, and made a lot of mistakes, which ended in the tank splitting because I moved it around one time too many! In an effort to keep the fish alive I put them in the nano tank which had not been cycled because it had been sat in the loft for a couple of years, inevitably, the fish died.
I replaced the broken tank it with a 55L tank which is now my main tank.
You can see how I set up and maintain each tank by following the links below: