How to set up a betta fish tank For betta fish tank set up you will need a 2 1/2 gallon tank minimum, water conditioner, bacteria supliment, and a filter. Possible extras you will need are aquarium salt and a heater. ***A few important things I failed to mention in my video*** Always try to cycle your tank before adding your new fish. Here is a link to my video about cycling your tank https://youtu.be/O61NAy6SKAE If you do add your betta fish before your tank is established (cycled) you will need to do more frequent water changes on your tank. 10 to 15% at least once a week to help keep ammonia levels at 0. Ammonia is toxic to fish and can make your betta fish sick. Cycling a tank usually takes between 6-8 weeks. Also do not set up your betta fish tank near any windows or in the line of direct sunlight, this can cause severe temperature fluctuations in your betta's tank and can also cause major problems with algae growth. If you do not have a heater on your fish tank and you find there is ever more than a 2-3 degree temperature fluctuation, you should add a heater to keep the temperature more stable for your betta fish.