20 to 39 Gallon Fish Tanks

The best selling 20-39 gallon aquarium brands are:

• Aqueon
• Tetra

A 30-gallon tank can weigh more than 250 pounds after you’ve added water, rocks, gravel and other decorations. Support and secure your tank with a sturdy aquarium stand that is designed to bear that much weight.

The answer depends on the size and species of each fish. As a general rule, you’ll need at least a gallon of tank space for each inch of every fully grown fish. To avoid overcrowding, always consult a Pet Care Center associate to confirm the appropriate number and type of fish for your aquarium.

Dimensions vary depending on the shape of the tank, but a 20 gallon tank typically measures approximately 30” L x 13” H x 13” W, while a 30 gallon tank typically measures about 36” L x 16” H x 16” W. Breeder aquariums tend to be taller but not as long. To ensure any aquarium you’re considering will fit into your home, always check the specific dimensions provided by the tank manufacturer on the product page.

The exact amount of gravel you’ll need will vary depending on your tank’s dimensions. Estimate about 1 to 2 pounds per gallon of water to achieve a 1- to 2-inch base.

A 20-39 gallon fish tank will require an aquarium pump and filter, substrate (like gravel or sand), decorations, lights, and aquarium heater. You'll also need a net, water conditioner, test kits, and an algae scrubber. Depending on the type of fish you want to keep, you may also need a protein skimmer and air pumps.