I just saw Crenicichla compressisceps (dwarf Pike cichlid) on Wet Spot Tropicals list, although I'd be hesitant to keep it in a 10 gal, maybe with no other fish(?) or maybe a 30-50 if other fish are to be housed with it).
The ones on their list are wild caught Brazil, , so I'd also be wary if your tap water is not naturally soft.
BTW below is Betta albimarginata (previously mentioned), which might be a more apropos for a 10 gal.
It is a mouth brooding Betta from Borneo.
Another wild type below
Betta edithae from the Malay penninsula
It is another mouthbrooder, spawning above.