Rasboras: Another popular choice for a 15-gallon aquarium is rasboras. These small, hardy fish come in a variety of colors and patterns, and are known for their peaceful nature. Some popular species of rasboras include harlequin rasboras, chili rasboras, and dwarf rasboras.
Danios: Danios are a great option for those looking for a more active fish. These small, fast-moving fish are often found in shades of blue, red, and yellow, and are known for their playful nature. Some popular species of danios include zebra danios, leopard danios, and celestial pearl danios.
Guppies: Guppies are a popular choice for beginners due to their hardiness and ease of care. These small, colorful fish come in a wide variety of colors and patterns, and are known for their ability to reproduce easily.
Platies: Platies are another livebearer, and are a good choice for those looking for a peaceful and easy-to-care-for fish. These small, colorful fish come in a variety of colors and patterns, and are known for their hardiness and adaptability.
Swordtails: Swordtails are a larger livebearer, and are a good choice for those looking for a more active and colorful fish. These fish come in a variety of colors and patterns, and are known for their long, sword-like tail fins.
Mollies: Mollies are a larger livebearer, and are a good choice for those looking for a peaceful and easy-to-care-for fish. These fish come in a variety of colors and patterns, and are known for their large, round bodies and long fins.
Corydoras: Corydoras are a small, peaceful catfish that are a good choice for those looking for a bottom-feeding fish. These fish come in a variety of colors and patterns, and are known for their armored bodies and barbels.
Otocinclus: Otocinclus are a small, peaceful catfish that are a good choice for those looking for an algae-eating fish. These fish come in a variety of colors and patterns, and are known for their suckermouths and ability to clean algae from surfaces.
Shrimp: Shrimp are a great addition to any freshwater aquarium, and can help to clean the tank and provide a food source for other fish. Some popular species of shrimp include cherry shrimp, amano shrimp, and ghost shrimp.