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20 to 39 Gallon Fish Tanks

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20 to 39 Gallon Long Aquariums

Midsize aquariums are a great choice for new pet parents or anyone with limited space or budget. A 20 gallon long aquarium is roomy enough to accommodate several fish (depending on their size and species) without overcrowding. With a 30 gallon fish tank, you’ll have even more choice in terms of fish variety. Starter tanks in this range are also ideal for both freshwater and saltwater enthusiasts. enthusiasts. Smaller tanks may suffice for some freshwater species, but a 29 gallon aquarium is the minimum requirement for most marine species.

Remember that choosing the right aquarium will impact many aspects of your fish-keeping adventure—from the species you can stock, to the water care and filtration required to keep your aquarium environment safe and your fish thriving. Be sure to explore our aquarium checklist for beginners and consult a Pet Care Center associate for helpful answers and recommendations. Then find your perfect aquarium, along with the right stand, lighting, décor, cleaning accessories and brushes and nets you’ll need. Or consider one of Petco’s convenient aquarium starter kits to help you create a healthy and beautiful home for your fish.

FAQs About 20 to 39 Gallon Aquariums

The best selling 20-39 gallon aquarium brands are:

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.

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