You have several options, but first we need to know the water parameters, and these are the hardness (GH) and pH primarily. You may be able to find this data on the website of your water authority, if you do not already know.
"Nano" fish which refers to small sized (at maturity) fish are well suited to this tank, and you could have quite a number. Most will be shoaling fish, meaning they must be in a group of their own species, say 10 or whatever depending upon the species. Many of these are soft water fish, but there are some lovely moderate to hard water fish too.
"Nano" fish which refers to small sized (at maturity) fish are well suited to this tank, and you could have quite a number. Most will be shoaling fish, meaning they must be in a group of their own species, say 10 or whatever depending upon the species. Many of these are soft water fish, but there are some lovely moderate to hard water fish too.