Actually, setting up and maintaining a large tank is easier than a small one. If something starts to go wrong in a big tank you have time to notice and adjust things to correct it before anything too terrible occurs. With small tanks the fish can be dead before you realise something is wrong
If you want hardy, I would suggest egg layers like danios, rasboras and tetras. Most of these are schooling fish though and need to be in a group of 6 or more. 60L is not very big so you will be limited in your choice. I would suggest cherry barbs, with corys on the bottom.