If cared for properly, they should die of old age, but typically, the most common cause of fish death in captivity is a water quality issue due to toxins that are too high.
They can die of one of the many, many betta diseases there are out there, or just of old age. If your fish is suffering badly, just put him/her in a plastic box with water and keep them in the fridge, they will freeze slowly and experience no pain what so ever. They live longer if kept in tanks, usually 7 years (Though eight years is not un-common) but, if kept in bowls- even though they will be just as happy- they will live 1-3 years.
Bettas gulp air. The only reason a Betta would 'drown' is if for whatever reason, it couldn't get to the surface of the water. This could be because it was sick and unable to swim properly, because it was harassed by more aggressive fish, the current in the tank prevented it from being able to 'rest' near the surface, or because it got caught on or under something in the aquarium. I have had bettas in many different sized aquariums and have never had a problem with 'drowning'.
No, betta fish are best as solitary fish, and unless they are going to mate, they do not swim together
Feed Betta little peice of a boiled Pea.
A dying betta fish may appear lethargic, have clamped fins, faded color, and may struggle to swim or breathe. Signs of distress in a betta fish include loss of appetite, gasping at the water's surface, unusual swimming behavior, and visible physical injuries or abnormalities. It is important to monitor your betta fish closely for any of these signs and seek veterinary care if needed.
it dies or it will only swim in circles
Wild bettas primarily eat insect larva that floats on the surface of the water, like mosquito larva. If they swim by it and it wriggles, they eat it.
Betta fish may lay on their side due to stress, illness, or poor water quality. It could also be a sign of swim bladder disorder, which affects their ability to swim properly.
No they cant it is impossible
Most fish swim away, or hide. Betta, on the other hand, LOVE to fight.
Fish do not normally "float around" they swim. If your fish is floating/sinking then it is probably dead.
all fresh water fish
If the water surface is frozen, fish continue to swim.
yes, it's because of they're large fins