Water quality is not to important for bettas because they do not breath through the water, but instead have a lung which they fill at the surface. They can become rather sick though if there is cool air over warm water and so drafts should not be allowed. This is especially true for young fry.

Water temperature should be between 73 and 83 degrees F (22 to 30 C) the higher only when breeding and when fry are young.

Water changes should be done regularly though since and infections in the water can still spread to the fish. Male bettas must be kept separate from other males unless they are in a large aquarium where territories can be staked.

It is important when doing water changes to try and not destroy any nests which they have built, this is highly stressful for the fish. As well betta get along well with nearly all other fish and since other fish are undoubtedly in the aquarium as well water changes should still be done.

Females can be kept together in the same tank and will not fight with each others the way males do. However, since these are labyrinth fish which breath air from the surface and not from the water they can be kept in small containers, but it is not recommended this be done for a long time because it is stressful.