Small fish species are typically defined as those that grow to a length of less than 15 centimeters (6 inches). These fish can be found in various aquatic environments, including freshwater rivers, lakes, and oceans. Examples of small fish include guppies, neon tetras, and minnows. They often play essential roles in their ecosystems, serving as prey for larger fish and contributing to the food web. Many small fish species are popular in the aquarium trade due to their vibrant colors and manageable size. They are generally easier to care for than larger species, making them suitable for beginners. Additionally, small fish often exhibit interesting behaviors and social interactions, enhancing the experience of keeping an aquarium.