no
other fantails.
The Fantails set out beyond the rainforest level of the world, they also live near human habitation.
There are so many possibilities. First of all, freshwater or salt? For fresh waters you can fit on common goldfish or comet,or 2 fantails,or a few guppies, or 2 FEMALE bettas, or 3 tetras, or 2 gouramis, or a few dragonfish, and you can add a few ghost shrimp with any of these fish except the dragonfish, and if you add some with the bettas make sure to keep the ghost shrimp in there for a couple days BEFORE adding the bettas.
it can live more than 50 years.
nothing they have to live by themselves
yes
NO! They are freshwater fish.
Contrary to common belief, bettas DO NOT live in tiny puddles or footprints. Bettas live in rice patties in the far east. These rice patties are the size of the drainage ditches along most major highways, and are stacked next to each other for hundreds of acres. Male bettas often claim entire patties as their territory
Malaysia and Indonesia.
Fantails are fish and fish do not drink. So the answer is 'Nothing'.
Daphnia, mosquito larvae, and brine shrimp are good choices for bettas.
Bettas only live a couple of years.