Most of the time, the Betta Splendens you see in pet stores are males. Males have long, flowing fins and tend to have brighter and more attractive colors than females. Females have short fins and an ovipositor located between their ventral and anal fins. An ovipositor is a small white structure that resembles a bead. The ovipositor is where the eggs are released and only females have it. Females often have a milder temperament than males but don't count on this. Males can be very viscous but it depends on their personalities. Females too can be just as mean as males and will attack each other so they should be kept separately unless they were raised together.
Most of the time at pet stores Bettas are kept in very small, cup -sized containers where they must curl or curve their bodies to fit. Bettas can live like this for a while but they should not be kept in such a small a container once you bring them home. They should be kept in a container that holds a quart of water or larger. If you can possibly keep them in a larger container please do so. Breeders who need to fit over 100 fish into a small area but still keep them healthy mainly keep Bettas keep in quart-sized jars. These jars must be changed every other day or so or they are not ideal containers for a pet betta.
I recommend keeping a pet Betta in a small tank 5 gallons or larger. I have found that they are much happier in this size although some Bettas do not adapt well from being switched from a very small container to a fish tank. If this is the case, then start with a shallow gallon tank or bowl and every month or so, after they have adjusted to a gallon of water try and move them into the 5-gallon again. Some Bettas will never adapt to larger volumes of water. If they are happy in their current gallon bowl and they are given proper water changes then don't worry about giving them a larger container.
Regardless of the size of the container you keep them in, Bettas seem to enjoy a plant and should be provided with one. I keep java moss in my Bettas jars and they seem much more active than without plants. Bettas in smaller containers that need frequent water changes do not need gravel in their tank. It is a hassle to take all of the gravel out, clean the jar and replace everything once a week. Tanks 5 gallons or larger require less frequent water changes of smaller volumes. Approximately 20% of the water should be changed every month or two on tanks this size. I would recommend adding gravel to these tanks because it helps in a number of things.
Fish are less stressed in environments that replicate their natural environments as close as possible. Gravel helps the fish to feel more relaxed and they adjust quicker to their new environment. This makes for a healthier, happier, brighter colored fish that is more active and amusing to watch.
Gravel provides a surface for helpful bacteria to grow on resulting in a healthier and cleaner environment for your Betta. For more information on helpful bacteria and the nitrate cycle visit the AquaLink column "Getting Your Hands Wet".
Gravel also provides a substrate for live plants to grow in. Live plants create a more natural environment for the Betta and aid in breaking down wastes that are excreted by the fish.
Lastly, gravel makes a tank more natural looking and aesthetically pleasing.
**Warning** : "Betta in a Vase" products have hit the market. These products usually inform the buyer that they are maintenance free and the betta does not have to be fed. This could be fatal for your betta! Learn more about it here.
Regardless of the size of the container you keep your Betta in you will need to change some or all of the water. Ammonia and other toxic chemicals build up in the water due to fish waste and left over food. For small containers fewer than 5 gallons 100% water changes will need to be done. The frequency at which they are done depends on their size. The greater the volume of water, the more diluted the waste and the less often the water must be changed. For quart-sized jars it is best to change the water every 2 to 3 days. For gallon containers the water should be changed once week to once every week and a half. Plants can lengthen the amount of time between changes by 2 or 3 days but this should not be used as an excuse not to change the water. Occasionally when I go on vacation for 3 or 4 days I am not able to change my quart jars as often as they should be. Since I place plants in all of my jars and tanks I can go on vacation comforted by the fact that the plants will keep the ammonia at bay for a day or two. For tanks 5 gallons or larger the water should not ever be completely changed unless you are tearing down the tank or you have identified a problem and the best way to fix it is to clean the tank out and restart it. Please visit the "Getting Your Hands Wet" link above to learn why it is not recommended to do 100% water changes on larger, established tanks. The water on tanks this size and larger only need to be change once every month or month and a half. Only 20%-30% of the water should be changed at a time to help preserve the water conditions.
Bettas should be kept at temperatures that range from 70-85 degrees F. If the temperature drops below 70, the fish's metabolism slows and they become listless. They eat less, their colors dull and they are more vulnerable to diseases. If the temperature rises above 85 the fish becomes stressed and again, is more vulnerable to diseases. To keep the temp stable, buy a small 25 - 50 watt heater. If the container the Betta is kept in is smaller than 5 gallons, a heater can do more harm than good so just try and keep the Betta in a warm place (not in a window seal or anywhere else that receives direct sun light because the temperature in the tank can sky rocket and stress or even kill the Betta). Don't be too worried about the temperature of your Betta's home; they are hardy fish and can survive in water that is on the cooler side but if it is at all possible to provide them with a warmer environment please do so.
In the wild, Bettas feed on insects and their larva or nymphs, with the majority of their diet consisting of mosquito larva. In the house however, mosquito larva can be a problem once they turn in to flying pest. There are many other alternatives thanks to fish food manufactures. I recommend Hikari brand foods. Many people feed their Bettas Hikari Betta Bio Gold with good results. My picky Bettas don't like it but they love Chiclid Gold baby sized pellets. Although a Betta can live it's whole life on a manufactured food such as Hikari pellets, they are much happier when their diet is supplemented or replaced with live or frozen or freeze dried foods. A popular frozen choice is bloodworms. They come in small rectangles and all you have to do is cut off a little and add it to some fresh water to defrost it then dump it in the Betta's bowl and watch them go nuts! Bloodworms also come in a freeze-dried form. Live blood worms can be found in the bottom mushy layer of ponds. These can be collected and fed to your fish. I collect my live bloodworms from the sides of dirty horse troughs during the spring and summer months. For more information on bloodworms take a look at Culture of Blood Worms. Be careful when collecting any live food you have not grown yourself because you can accidentally get a few pest that can be harmful to your fish. Daphnia is a type of very small crustacean that can be collected from ponds, fed in frozen form or fed in freeze dried form. Other additions to your Betta's diet can be black worms, brine shrimp, regular shrimp, crab meat, and liver. Check out the Fish Food Page for more information on foods.