The first important fact about Beta Fish care or Betta fish care is that they are tropical fish and need to be kept in warm areas. The water needs to be kept between 70 and 80 degrees. Any area that is at a constant room temperature will do.
If you notice your fish has refused to eat check the water to see if it is warm enough. Betas will often refuse to eat when the water is to cold for them. 
Beta fish or Betta fish are quite versatile and are well adapted to small tanks or bowls. I've even known people to put their beta fish in small glass containers. However I would not recommend putting them in anything smaller then a fish bowl or the New SpongeBob SquarePants Beta tank.
Check out the strange Bubble fish bowl in bohemian Glass
Beta Fish Care and Filters
Since Beta fish or Betta fish, require less oxygen then many other fresh water fish they can be placed in tanks like the Argos Tropical Fish Tank. without a filtration/aeration system.
However, if you do not have a filtration system the bowl or tank will require more frequent water changes (at least once a week) thus exposing your beta fish to unnecessary stress. A filtration system also reduces the risk of disease in beta fish. Filters such as the Hagen fluval plus filter are ideal for smaller tanks, Click here.
If you do have a filter in your tank it should never be turned off except for cleaning. There are important colonies of beneficial bacteria that grow in it and if it gets turned off for more than a few minutes the bacteria begin to die. These bacteria are what consume the fish waste toxins.
Check out all our Beta fish filters here