these are all from same waters or can handle colder temperatures:
Botia dayi / rostrata
weather Loach
Badis
apistogramma
Dwerggourami”?
Betta coccina
Corydoras aeneus
trilineatus, aneus, trilliniatus, paleatus
Macropodus opercularis
Some in the list are to small and gone be food. i wouldnt try corys aswell since if he eats them he might be dead.
I tried botia's but they bullied the snakehead. So i wouldnt try that either. those botias are mean.. i didnt know that.
I got 2 Macropodus opercularis and 2 weather loaches.
You could try that but weather loaches might get to big for your tank.
i wouldnt try goldfish since your not gone be able to feed them with a snakehead or you might have an obese snakehead if you try to feed to goldfish.