Stocking 10 litre ? (suggestions wanted)

[confusedfishowner101]

Hi all,
I currently have a forty litre tank (whcihc I believe converts to around 10.5 gallon) that is empty. It is equipped with a heater and filter.
I was looking for some stocking suggestions.
I originally thought a Betta sorority tank but after reading articles I noticed that success varys with the Betta's and buying five which where I live equates to around $55. This seems an awful lot of money for a tank that seems like it will not work out?
So I was looking for suggestions for the stocking. Any suggestions are welcome

 

[NickAu]

$55. This seems an awful lot of money

The Dumbo female in my clip was $40 and the double tail $35

And this is the sorority I lost when we had major flooding

Betta sororities can be fun,

 

[LyraGuppi]

Do you know the hardness of your water?