As much as pet fish overall have high mortality rate due to the lack of proper care, betta is probably one of the most abused fish species in aquarium trade. Many people mistakenly think a betta can live in a soup cup, without filtration nor heater. This is totally wrong. Yes, you see all the betta in small cups at pet stores. It is because the pet stores can nothing other than profit. Since two betta can't be in the same fish tank, it is not economical for them to have one setup for each betta. So they throw them into small cups and hopefully they can be sold before dying. Every time I go to pet stores, I see dead or near dead betta in those cups. It's no place for them.
As a tropical fish, betta need a heater. As with all fish, betta needs a filter system in their tanks to keep the aquarium nitrogen cycle going. Their tanks can't be too small either, since too small of a tank are likely have fluctuation in water temperature and water chemistry which can be deadly to any tropical fish.
With proper care, a betta can live up to 4~7 years.
