Aquarium swimmers are two types of fish, the Tetra and the Guppy. The Tetra is a small freshwater fish that is found in many aquariums. It is known for its bright colors and peaceful nature. The Guppy is a small, colorful fish that is also found in many aquariums. It is known for its hardiness and ability to adapt to different environments. Both the Tetra and the Guppy are popular choices for aquariums due to their attractive appearance and easy care requirements.