Siamese fighting fish (more commonly known as beta fish) are a unique breed of tropical fish. They are almost always kept in individual aquariums because of their propensity for fighting. When placed with other types of fish, they will often fight or eat anything smaller than them.
These fish are quite finicky and as carnivores, they will not eat regular tropical fish food. You will need to provide mealworms, insect larvae or other types of meat or high protein food. Be careful, since Siamese fighting fish can become constipated, a condition which is very dangerous for them. You'll notice a swollen stomach if this occurs.
Like many tropical fish, these ones require the regular aquarium supplies for their fish tanks, including aquarium filters and pumps. They can breathe air by gulping it through their mouths and you will frequently see them at the top of the fish tank, breathing. The males of the species use this ability to blow bubbles underwater, creating bubble nests when they are ready to mate. The males will do this even if they have no contact with a female.
In the fish tank, it is important to keep males separated. They may be placed in the same tank, but with a partition to ensure they don't hurt each other. This is also true of females and males, since they tend to be rather aggressive. While some of this species are quite mellow and will happily cohabit the tank with other fish, it is usually best to keep them relatively isolated. They also like aquarium decorations that allow them to hide and establish territories, such as rocks and plants.
Siamese fighting fish are a beautiful addition to any aquarium. They do require special care, however, so be sure to educate yourself before purchasing one. Your local pet store will be able to give you tips.