A rectangular fish tank is the most popular one due to its ease of construction, affordable price, and ability to be just as beautiful as any other aquarium. Additionally, rectangular tanks are much easier to aquascape compared to other shapes while still providing your fish with plenty of space to swim and explore.

 

Your natural reaction may be to sort rectangular aquariums by gallons - which is a measure of volume often distorted by its height and width. Since your floor space may be limited, your best bet is to shop rectangle aquariums by length instead.