The Siamese fighting fish or more commonly known as betta (Betta Splendens) is a very popular fish for smaller fish bowls or tanks. They are easy to keep, and have a special organ, known as a labyrith, which allows the fish to breathe by sucking air from the surface for the water.
Bettas can be very picky with their food sometimes, but like all fish they need a varied diet. Bettas will generally take dry floating pellet, but its good to give them some frozen brineshrimp, daphnia or bloodworms as a treat. Dried bloodworms are a good option for those that can't bear to keep frozen bloodworms in your freezer.