The captivating betta fish is ubiquitous in most fish and pet stores but unfortunately, nearly as common is a cloud of misinformation that follows them, perpetuated (quite innocently) by uninformed employees and patrons alike. Below, we set out some of the misconceptions circulating about bettas and some facts about their natural habitats and care.


If you've heard a myth that we haven't included here, or a "fact" that doesn't seem quite right, please CONTACT US and let us know! We would love to research it and add it to our list.


MYTH - In the wild, bettas live in filthy water. They come from mud puddles!

FACT - The waters that bettas originate in may have little or no water movement, but as a part of a complete ecosystem, they are not filthy in the way that a small, unkempt bowl is.

  • A betta's native waters are often stained a dark brown color, like tea, by leaves that have fallen into the water and leached tannins into it. While this may make the water appear "filthy", this is not actually so. These tannins are not at all harmful to fish, while true filth certainly is.
  • A betta's native waters include rich soils in which plants, and beneficial microorganisms (see THE NITROGEN CYCLE) grow. The plants and microorganisms consume harmful wastes that fish produce - removing filth.
    • The soil may be disturbed, creating muddy, murky water temporarily, but this is still a balanced ecosystem and is far from filthy.


While all of this may give a betta's natural habitat the appearance of being dirty, it is actually a well balanced ecosystem designed to process and remove harmful waste, allowing fish to thrive.


Conversely, in a bowl with no filtration (this is the role that plants and microorganisms play in nature), the liquid and solid waste that a fish produces quickly builds up to toxic levels, resulting in true filth. Neither bettas, nor any other fish, are adapted to live in conditions like this, and a fish forced to endure this will suffer and die prematurely.

MYTH - Bettas prefer small spaces. (a continuation of the mud puddle myth)

FACT - Their natural environments may be shallow, but they are also vast and heavily planted, and bettas are far from sedentary fish. Their labyrinth organ which allows them to breathe atmospheric oxygen evolved to address low water movement (and thus low oxygen content) of their native waters, but it is also exploited by keeping them in tiny, oxygen-poor vase/bowl environments that non-labyrinth fish could not survive in. They may be uncomfortable with large open spaces, as they feel exposed, but they are not uncomfortable with large water volumes.

MYTH - Water left to sit overnight in an uncovered container ("aged" water) doesn't need water conditioner as the harmful chemicals in it have evaporated off.

FACT - Chlorine, chloramines, ammonia and possibly other chemicals are added to municipal water systems to kill bacteria. While Chlorine will evaporate off; chloramines will not, and are chosen to sterilize water because of this stability. Water conditioner is necessary to neutralize the toxic chloramines that would otherwise kill the fish.


However, it is still a good idea to "age" your water as well as adding a water conditioner.  Tap water systems are pressurized and water straight out of your tap is high in dissolved gasses which can harm your fish if not allowed to dissipate. See our article on GAS BUBBLE DISEASE for more information.


MYTH - Bettas are fine at room temperature. They don't need heaters.

FACT – Bettas are tropical fish originating in Thailand and SE Asia, where temperatures average 30° C or more - well above room temperature in most homes! (my heater is set to about 15-20 C)


As cold blooded animals, fish’ metabolisms are able to slow to cope with too-cold temperatures, but this comes at a cost, hindering their immune system and slowing their digestion, further increasing their risk of constipation/impaction.


If temperatures dip too low, bettas can and do freeze to death.

MYTH - Bettas don't need filters. In fact, bettas will drown if you put them in tanks with filters!

FACT – Without a filter, the only way to remove ammonia is through water changes. Even done several times per day, partial water changes will never remove all of the ammonia in the tank, and the residual amount left would continue to grow over time. The only way to fully remove ammonia would be through 100% water changes, which can be dangerous for fish, thus necessitating a filter. – see “A Note About Water Changes” in the maintenance section for an explanation of this. The second part of this myth has no basis in fact as bettas breathe in the same way as other fish, with the addition of the labyrinth organ.

MYTH - But bettas breathe air, so they mustn't need filters.

FACT - There are two main things that are wrong with this one:


  • Filters actually have little to no effect on oxygen in the aquarium water - as their name suggests, the purpose of a filter is to filter certain things out of the water. Specifically, filters are needed to remove/filter out toxic ammonia that would otherwise kill your fish.
    • There is equipment used in aquariums to increase the oxygen in the water - but it's not a filter - the parts are called "air stones" and "air pumps" which are connected together by "air line tubing".  These air stones create streams of bubbles in the water.


  • Bettas aren't the only fish who can breathe air! However, they are one of the only fish that is kept in tiny, unfiltered bowls, and this isn't right.
    • Bettas are one of a group of many labyrinth fish - fish that posses the lung-like organ that allows them to breathe air at the water's surface
    • Other labyrinth fish include:
      • Gouramis; and
      • Paradise fish
    • However, gouramis and paradise fish are usually larger and/or more sensitive than bettas, and thus can not be marketed in such unsuitable tanks


  • Consider goldfish (another animal that should NOT be kept in a bowl) 
    • Goldfish are not able to breathe air, but they are routinely marketed in bowls
    • However, goldfish are very hardy and are able to survive the toxic conditions that bowls create for days or months.
    • The natural lifespan of your average goldfish is 15 years! "They only live for a few months" is another urban legend, likely created as uninformed fishkeepers watched their pets succumb to ammonia-poisoning in bowls!

MYTH - Bettas will feed on the roots and leaves of plants growing in their bowls.

FACT – Bettas are strict carnivores in the wild, feeding on insects and zooplankton. They do not naturally feed on plant matter, and their digestive system is not designed for it. They will not be sustained by nibbling on a plant in their tank and must be fed an appropriate diet. (see the FEEDING section for a discussion of this)