Officially called Tai Fish Fighting, two male Betta fish are placed in a tank to fight. One will die. Betta's are one of the worst treated fish breed. You can buy them in the pet store, and they come in small cups. The reason for this is selling. People will want to buy them if it looks like they have more of a choise, and if they do not have to go though the hassle of catching the fish with a net. People in pet stores also give awful information. Betta need clean filtered water just as any other fish do. they are vulnerable to bloat and fungal infections and unfiltered water is not good for them. Betta need enrichments and stimulation, like plants, caves, toys, driftwood, novel items every now and then to investigate. They must not have plastic plants or sharp edges, and they must have a fine sand substrate. They need a strictly constant temperature and they need protecting from emotional stress. They must have their tank to themself if male and do not need companionship from any fish or snails or shrimps. They are happier absolutely alone. Female betta fish are social and should live in small groups. The tank must be large enough for a filter to run without creating a strong current. They need the right diet. Some of the best food to feed your Betta is: -Frozen meal worms -Frozen brime shrimp