Thus, the subjects of this experiment are the Siamese fighting fish (Betta splendens). Betta splendens are freshwater fish often found in the marshes, ponds, or slow-moving streams of Southeast Asia, and are available in pet stores worldwide. They are a popular model for studying reproductive and aggressive behavior around the world, as male Betta splendens have a tendency to defend their territory from other fish . Betta splendens are carnivorous animals who, in nature, mostly consume insects and insect larvae near their surroundings. Male Betta splendens build bubble nests for their babies with their mouths and attract female Betta splendens to them. When the female begins to lay eggs, the male retrieves them and deposits them in the nest . The males then chase the female away due to their inherent aggressive behaviors and guard the nest against intruders and predators until the eggs hatch out. Male Betta splendens will exhibit very aggressive behavior against other fish such as anal fin spreading, or attacking the opponent fish, as they act as territory-holders once they are used to their habitat . If two male Betta Splendens can see each other without an escape route, they will fight and, in some cases, die due to extreme fighting. Since these are characteristics common to Betta Splendens, we can use these as indicators for changes in behavior due to the consumption of caffeine .