A 20-gallon fish tank is a versatile choice, suitable for both beginner and experienced aquarists. It provides ample space for a small community of freshwater or saltwater fish while remaining compact enough to fit on most stands or desktops. Whether you're planning a peaceful planted aquarium or a dynamic reef setup, this mid-sized tank offers the flexibility and volume to bring your vision to life. Benefits of 20-gallon size tanks include:
A 20-gallon aquarium is also a great next step when you want to upgrade from a small tank to a larger setup. With Chewy’s wide selection of tanks, tank kits, and accessories, you’ll have everything you need to start or expand your fishkeeping journey. You can even set up Autoship for routine supplies like filters and food to keep your aquatic habitat running smoothly.
Many types of fish can live in a 20-gallon tank or smaller. It makes a great habitat for a variety of smaller fish such as tetras, guppies, platies, rasboras, and cory catfish. Be sure to research species compatibility and avoid overcrowding to ensure a healthy environment for your fish.
A 20-gallon tank is big enough for a beginner and small enough not to be too complex. Opinions vary on the ideal size for a starter tank, but many experts recommend the 20-gallon for its manageable size and ease of maintenance. This mid-size capacity provides enough room for stable water conditions, and it can house a greater variety of fish than smaller tanks. These factors help make 20-gallon tanks fairly easy to maintain and very rewarding to manage.
The equipment you need for a 20 gallon fish tank will vary depending on your setup. Saltwater tanks require specialized types of equipment, but freshwater habitats are a bit simpler. For a basic 20-gallon freshwater aquarium setup, you'll usually need a filter, heater (for tropical fish), lighting, substrate, and decorations. Additional equipment like an air pump, thermometer, water testing kit, and a gravel vacuum and siphon for water changes will make it easier for you to maintain a healthy environment for your fish.