Myth: Bettas can live in tiny bowls
People think “In pet stores they keep bettas in tiny containers... the bowl I am getting is a castle compared to that. My betta will be so happy.” OR “In any case, bettas live in small stagnant pools in the wild and, therefore, it is perfectly appropriate to put them in tiny bowls/tanks.” Unfortunately, these are not a good suppositions.
The small containers bettas are kept in the stores are chock full of chemicals to keep bacteria, fungus and parasites at bay. They are unhealthy places for any fish to be in, and they are not meant to be long term homes.
Bettas do live in shallow pools in rice fields in Thailand. But, these puddles are interconnected And can extend for miles. If the puddle the betta is in gets stagnant, the betta has the ability to (and they do indeed) swim to another puddle or, if it is the dry season, jump up to 6 inches into another pool (or even from puddle to puddle until they reach one that has appropriate parameters).
In addition, the water they are in is continually refreshed with rainwater and decaying matter. In an aquarium, they are stuck and it is up to us to refresh the water and keep their tanks clean and non-toxic through routine partial water changes.
The minimum size tank that you should keep a betta in is 3 gallons. 5-10 gallons is ideal.
The smaller the tank the more you have to work on upkeep.
Myth: Bettas can live without heaters
Bettas originate in Thailand. This is a tropical country and they are tropical fish. The mean temperature in Thailand has been 27C (80F) over the last fifty years. Bettas do need heaters if not kept in a tropical country.
Myth: Bettas do not need a filter
Bettas breathe oxygen from the surface so do not need a filter.
Yes, Bettas do have labyrinth organs which allow them to rise to the surface and breathe oxygen, but this is just gives them supplemental oxygen. Bettas also absorb oxygen through their gills. A filter not only filters the water but also supplies added oxygen to the water. ALL FISH INCLUDING BETTAS NEED A FILTER.
Because betta have been bred to have elaborate fins, the filter flow should be gentle. It is best if you get an adjustable filter and run it at minimum flow. If you find that your betta is struggling against the flow or intake of your filter you can baffle it in several ways: