Oh ok, thanks, what fish are suitable then?
In very general terms, you should look at fish that originate (meaning, in the wild habitat) from South America and SE Asia. Forget all livebearers as they need harder water. Some of the rainbowfish from northern Australia and New Guinea will work. Most characins (which includes tetras, pencilfish and hatchetfish), rasboras, danios, barbs, most catfish (cory cats for example), gourami, dwarf cichlids, some of the loaches. Obviously these cannot all be combined, I am only giving you groups to look into. And the eventual size of tank you get (the 90cm or 120 cm length) needs to be kept in mind. Many of the mentioned fish are shoaling, meaning they must be in groups; while there are minimum numbers like six for many of them, it will always be better for the fish to have more in the group. So for example, a group of 15 rummynose tetras will be much healthier than would a group of six or seven.