Caring For Your Betta (Siamese Fighting Fish)
How to care for an adult betta (Siamese fighting fish), and avoid common mistakes regarding the bowl's water.
When you go to a pet store, you'll find rows of small bowls, each containing one colorful fish. These are male Siamese fighting fish (more properly known as a betta) and the way you find them in the pet store is essentially how they should be kept.
Bettas can be kept in small containers because they are able to breathe air, like humans, as well as water. Keep the water between 70 and 80 degrees, and don't let the temperature change too quickly. Keep the bowl away from appliances that produce a lot of heat.
IMPORTANT: Only ONE betta per bowl! They're called "fighting fish" for a reason. They are highly territorial animals and will react violently if two are placed in the same container. You can see the preliminary phase of their fighting, the threat display, if you put a mirror up against the bowl. Notice the raised gill covers, which makes the betta look bigger.
Change the water in the bowl when it starts to look cloudy, about once a week. Let the water age at least 24 hours, to release some of the chemicals. After transfering the betta to a container (with either the old water or the water you're going to use) clean the bowl with mild soap, and rinse thoroughly. Also rinse any decorations (rocks, shells, plastic plants, etc.) before filling the bowl with the aged water, and releasing your Siamese fighting fish.
The pet store where you bought your betta will have food as well, probably freeze-dried blood worms. (This sounds a lot more horrific than it actually is.) Feed your Siamese fighting fish two or three times a day, only what he will eat in a few minutes. Overfeeding will make the water cloud faster, and your betta will be more likely to get ill.
One last note: pet stores usually don't carry female bettas, because they tend to be less colorful and showy than the males. Also, people are usually just looking for a nice pet, not a breeding hobby. If this is your intention, then I suggest doing some serious research before you start!