Everyone keeps bettas in those tiny globes, so they must be almost the only common aquarium fish that can tolerate high concentrations of ammonia waste in the water, right?

No. Bettas do have the ability to breathe air, however the ammonia still burns their gills and will have ill effects on their overall health.

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"Being ignorant is not so much a Shame, as being unwilling to learn".-- Benjamin Franklin

Not really. Bettas can live quite a long time, and when they are kept in those bowls, they normally only last a few months to a few years (if they are lucky.)

They actually need space like any other fish does, plus filtration and a heater (they like the heat in the 80's.)

It makes me mad that fish stores still sell those tiny glass bowls for Bettas. Ppl see them displayed that way, and figure it's good enough to keep them that way at home. I've killed many a Betta doing this before I leaned.

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20g and 36g Heavily Planted

No,everyone does not keep their bettas in those tiny globe.On the contrary many people are discovering that even though a betta is an anabantid,they still need clean,fresh water to thrive.They do so much better in an aquarium setup with filtration heat and plants.

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http://bountifulbettas.blogspot.com/

"Come to the dark side....we have cookies...and filters/heaters/and water changes!"

Bettas can tolerate being in small globes because they breath air. They don'ti like Ammonia any more than other fish but they can tolerate ammonia damage to their lungs better than many other fish can because they can get O2 through their air brreathing system. In my local Big Box stores they keep their Betta globes pretty clean. Bettas are designed to tolerate water with a low O2 content but they still prosper in clean water.

Yes, they can breath atmospheric air, but they still get gill damage from the ammonia just like any other fish. They also get wounds on their bodies from ammonia burns and bacteria from dirty water, which can lead to infections and death. In the wild even if they are in small areas of water, that water is constantly replenished and freshened with rain and fun off. They should never be kept in little globes. Like any other fish, they really do need a proper aquarium set up to thrive and not merely "get by."

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20g and 36g Heavily Planted

In a small bowl with high ammonia some fish would die in minutes, some in hrs or days, bettas are capable of lasting longer than most, maybe months, but won't thrive. Keeping a betta alive for a couple of months is kind of like keeping a dog alive for less than a year, not what you should be aiming for. Regular water changes, live plants, and a warm room without temperature drops are factors that might extend the life of the betta further but will never be as good as a proper heated filtered tank.

Breeders often keep their fish in small bowls but it's a bit different because they keep them in a heated fish room and do daily water changes, not to mention having much more experience.

No, they certainly are not the only fish that can survive a miserable existence in flesh/gill/eye burning water for some time, they are just the poor souls the pet trade chose to exploit.

Well put.

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"Being ignorant is not so much a Shame, as being unwilling to learn".-- Benjamin Franklin

Bettas will thank you for putting them in a proper aquarium.they become a pet not just a fish,also the females will live peacefully with other tank mates. I have 7 in a 20 gallon,and have had males in with tetras and corys if you get a mild male.

The females may live together peacefully. Every sorority attempt is not successful.