Tropical freshwater fish are a diverse group of species that inhabit the warm, shallow waters of tropical regions. Two of the most common types of tropical freshwater fish are cichlids and tetras. Cichlids are a large family of fish that are found in both fresh and saltwater habitats. They are characterized by their bright colors and aggressive behavior. Tetras are small, colorful fish that are popular in home aquariums. They are known for their peaceful nature and ability to school together.