They are famous for being extremely territorial and they attack anything they think might be another male of their species.
Betas should be kept in large, filtered tanks with still water and many hiding places to best duplicate their natural home. At least 10 gallons is recommended, and 50% to 75% of the tank should consist of hiding places for the beta. Betas love to hide and this will reduce stress. The water temperature of your tank should be between 78 and 80 degrees, and never drop below 74 degrees. Most people will need a heater to maintain these temperatures. More than one beta can be kept in a tank, but only one male.
Remember that betas are carnivores. They can be fed frozen or processed meat, though the beta should have consumed his entire meal after two minutes or you have overfed it. Uneaten food floating in the tank can lead to a buildup of bacteria that will hurt your beta’s immune system. They should be fed about once a day.
Change the water in the tank frequently, as the beta lives naturally in places where the water is frequently renewed.
Siamese Fighting Fish can be kept with other kinds of fish, but remember that they are extremely territorial. Avoid fish that look similar to betas, and fish that like to rip at fins.
Take care of your beta and you will be able to enjoy their beautiful plumage for years to come.