Siamese fighting fish, or Bettas, are native to Siam, (now known as Thailand), and often live in murky, still, muddy waters in creek beds. Durring the dry season, these fish will often be stranded in small puddles and in REAL dry seasons, can actually go without water for short periods of time. Even more remarkable, they can survive by burying themselves in muddy bottoms until water returns to the pool again. That is likely how they developed a labyrinth organ which enables Siamese fighting fish to take in oxygen from the surface of the water rather from the water itself. Still, to keep these fish in small bowls stresses them out because the water becomes polluted and toxic from fish droppings and frequent changing of the water.
You've often heard how aggressive these fish are, and it's true especially if they are kept in close quarters with other fish. They seem to be completely content to live a solitary life. Mating can be complex because of their nature. The male will build a bubble nest that is made from mucus. Once the nest is built, the male will allow a female into his territory and mate. The female is then chased off and the male will tend to the eggs and protect them. Babies hatch out 24-48 hours later and will leave the nest 2-3 days later. At that point, the babies are on their own.
This fish set-up is ideal for Siamese Fighting fish, as the plants provide a filtering effect on the water as well as providing oxygen. Keeping them out of direct sunlight and in lower light discourages algae to grow and therefore less often water changes. In fact, we never change the water for Cactus Burt, Glass Earths' pet fish. Instead, we regularly top his water up only. That makes him very happy and likely to live a full lifespan of 3-5 years!